"I purchsed a pet screen door by this manufacturer- (still the only one who makes them i believe) probably a good 5-6 or more years ago, and am still using the original one! I put it in a small window in my laundry room, which goes out by an enclosed walkway into an outdoor cat pen. The cats just love it! It stays open just about year round- every winter i cover the whole window screen, and screen door, with clear plastic attached with double-sided tape- cutting thru the plastic, around the pet door frame with a knife after attaching the plastic, to make a "storm door" out of it- so that the window can stay open in all but the worst, coldest, windiest weather. It has seen some major wear and tear from cat clawing over the years and is now plasticked itself, and I will be replacing it soon i guess. but it is still functioning after all these years, and I will buy one again! it definitely makes for happy cats!!!
i have had the cats occasionally pull it free from the window screen (you have to be careful to leave enough screen inside the pieces for it to anchor solidly to) but i have never had any touble getting it to secure again! it is very durable and i have even hit it with a metal hammer or even stepped on it to get the two halves to attach together again, and it has never even cracked! pretty durable for plastic i would say!!!
I highly recommend it for cats."