So, this thing couldn't have come at a better time: my 14 year old labrador rescue came to me when he was 10 yrs old as a medical rescue following a harrowing ACL surgery. Long story short, he's only gotten worse with his mobility since then, but it's amazing how much will to live this guy still possesses. So, it was heartbreaking for me to witness over the last maybe 4 months a sudden decline in his ability (not in his DESIRE) to get around. I tried Wuffes supplements (they don't work, BTW.....not for us), and ironically, it seems they almost ACCELERATED his inability to be mobile. But - DANG....SERIOUSLY - this dog rises painfully like Lazarus in desperate attempts to follow me, true to his long-standing abandonment issues. Desperate to help him stay mobile enough to at least still accompany me outside for toileting purposes, and to keep his legs in motion ("motion is lotion [for the joints]"), and after reviewing more costly wheelchair options, I ultimately decided on this rear support wheelchair. 1.) HOW EASY IS IT TO PUT TOGETHER? It wasn't so bad after watching the online video instructions AND reading the instructions manual. I DO very much wish the pictures in the manual were a good bit larger (maybe they could do a picture-in-picture - type thing, where there is an overall picture of an assembly step, and a smaller picture of a CLOSEUP of the assembly); basically, some of the pictures were way too small to see, but the video made up for what the assembly book lacked, and vice-versa. ******BIGGEST ISSUE ENCOUNTERED WITH THE ASSEMBLY INSTRUCTIONS: In NEITHER the book NOR in the video do they mention how to stop the LEFT AND RIGHT SIDE ARMS from sliding up and down loosely in the LEFT AND RIGHT WHEEL CONNECTORS once the entire wheelchair is otherwise assembled. This is, like.....THEEEEEEE most important step, because if it is not tightened, the entire rear wheel assembly (the WHOLE THING!!!) slips right off of the LEFT AND RIGHT SIDE ARMS, and falls to the ground if you try to lift the wheelchair by the UPPER REAR CROSSBAR. SOLUTION: I called customer support to find out how to secure the position of the RIGHT AND LEFT SIDE ARMS. "Helen" was SUPER helpful: she sent an email to me right away with picture diagrams to show me that there are two TINNNNNYYYY LIIIIIIIITTLE screws on each of the two WHEEL CONNECTORS (AKA, the rectangular shaped blocks attached to the SIDE ARMS). *THIIIIIIS is the reason you are given a smaller Allen key/wrench, but this is not explained in the book nor in the video!!! Once you assemble the wheelchair, and determine how high of a setting you need the rear support to be (specific to your dog's back leg lengths), you can lock each WHEEL CONNECTOR into their desired height positions on the left and right side arms by using the SMALL ALLEN KEY to tighten the two tiny little screws on each of the WHEEL CONNECTORS. (You should also tighten the two tiny little screws on each of the two UPPER CROSSBAR CONNECTORS, as well; this will prevent the UPPER REAR CROSSBAR from sliding up and down anytime you grab onto it to move the wheelchair.) *UPDATE (after 2 months of use following this tightening of screws): This tightening of the screws only works for a short period of time. Even though the "grip" held at first, the tiny screws have since slipped up the side arms, causing a physical groove up the arms where these screws were TRYING to support the weight of my doggie. *Pictured: See close up of wheel >>>My husband ended up drilling straight through the REAR WHEEL CONNECTORS, and put a physical bolt through the entire SIDE ARM and through the WHEEL CONNECTOR to keep the SIDE ARM from sliding down under the weight of my pup. Sadly, the two little screws being tightened to their maximum still was not enough to support his weight. HOW EASY WAS IT TO GET MAX INTO THE WHEELCHAIR ONCE ASSEMBLED? I give lots of credit to a combination of a few things that aided my ability to do this ALONE. I positioned the wheelchair with it backed up against a wall, side arms down on the ground, SPORTS HARNESS already attached to the wheelchair frame. I had Max standing on carpet (for traction so his front paws didn't slide out from under him). I held onto Max and supported his weight in his VERY trusty harness I'd used for a year prior to getting the wheelchair. (I recommend VERY highly the "COODEO Dog Lift Harness, Pet Support & Rehabilitation Sling Lift"). Using his two handles on his harness, I backed Max into the downed wheelchair that was backed against the wall. I held onto the front handle of his harness while lifting both back legs over and into the SPORTS HARNESS STRAPS. I then lifted the entire front end of the wheelchair up to meet the two buckles on either side of Max, and clipped each of the two buckles that are one-each on the sides of the front shoulders. VOILA!!! The design of this wheelchair is honestly pretty PERFECT, for the most part, just the way it is. It works VERY well, even though my SPECIFIC experience isn't the greatest. Max has demonstrated near-immediate use of the wheelchair, but is stubborn AH. Only when I have treats ready aplenty will he READILY follow me home, and ONLY if I am headed in the direction of the house. BE PATIENT! USE LOTS OF POSITIVE REINFORCEMENT! HAVE PLENTY OF TINY TASTY TREATS IN YOUR POCKET, AND REWARD YOUR DOG EVERY 12 FEET OR SO UNTIL HE GETS THE HANG OF IT. Max has demonstrated near-seamless use of the wheelchair a few times (we've only just started using it this week), but he can be a real "butt" sometimes, too.....which is why I love that grumpy old man enough to get him a wheelchair. He reminds me of ME. XD WHAT IMPROVEMENTS COULD BE MADE TO THE CONSTRUCTION OF THE WHEELCHAIR ITSELF? Plastic parts are great until they AREN'T. TBH, I feel the DESIGN of the wheelchair (especially being one of the most affordable ones you can find on the market) is great and works as intended (INCLUUUUDING giving the dog opportunity to void his bodily contents while strapped into the wheelchair; Max can easily pee, and has demonstrated the ability [not willingness] to do #2.) But the plastic FEMALE/MALE CLIPS at the front of the harness, and the O-CONNECTOR CLAMPS on the harness itself are NOT STRONG ENOUGH. I'd like to see a metal version of each of these parts, as the O-CONNECTOR CLAMP is already compromised in less than a week's use; the narrowing of the opening that is supposed to "click" into place once it's slid onto the SIDE ARM BOLT is already chipped. Therefore, it will already no longer "click" into position, and it slips off of the SIDE ARM BOLT - sometimes while Max is already suspended in the sports harness. These need to be made of METAL. As mentioned before, the MALE/FEMALE HARNESS BUCKLES that are positioned on either side of the dog's front shoulders (that strap the rear support to the front harness around your dog's neck/chest area) tend to DISCONNECT RANDOMLY/UNEXPECTEDLY at times. The quick fix is to keep an eye out that this might happen, and to hurriedly re-attach it, making sure the buckles on either front shoulder are securely snapped into place. Again, another part I think should be made of something more durable than plastic, or perhaps be made with a much more durable grade of plastic. HOW ABOUT THEM WHEELS? I thought I'd much have preferred the air tires over the foam ones, but TBH, I REALLY REALLY LIKE THE HARD FOAM TIRES! I love that they DON'T "give". I feel the hardness of the foam tires decrease the amount of weight of the tire, AND - because it's not "giving", there is much less friction for your dog to overcome. Aired tires would require, IMO, more upper body strength to pull over any surface. The only way I could see the air tires to be more useful is if there is risk of rocky terrain that could break chunks of foam tires off. The last thing I like most about the wheels is that they are slightly canted; the tops of the wheels are each at an angle to the ground's surface, which has already proven wonderful in that the tires to DRRRRAAAAAAAAAGGG across the entire walls of your home. The tires, in fact, don't touch the walls of your home AT ALL because of this. Only the bottom of the wheel, where the stance of the wheel is widest as it touches the ground, touches the baseboards. This = no having to repaint the walls when Max drives like he's had too much Boonesfarm or MadDog 20/20. WOULD I RECOMMEND THIS OVERALL???? YES. I sure as heck would. I knew this would be tough: my dog is going on 15 years old. He's a Lab. He should have been dead by now (poor guy). He has good days and he has bad days, but this has eased the burden of my having to basically FULLY carry him using the "COODEO Dog Lift Harness, Pet Support & Rehabilitation Sling Lift" upon which I'd become almost fully dependent the last few months before I received this wheelchair. It was too hard on my body to lift this doggie everywhere he needed to go. I don't always get great results when I use the wheelchair, but because Max has demonstrated his ability to use it effortlessly on his good days, I would say this is a great product. JUST BE PATIENT WITH YOUR DOGGIE, AND GIVE HIM TIME TO BUILD THE STRENGTH IN HIS UPPER BODY, AND THE TIME TO ADJUST TO HOW TO USE IT.