I had a 97 4Runner for 15 years. Never garaged. Never had an issue with Door Seals tearing. Early on, during cold weather (Portland, OR) moisture had frozen to the seals and pretty much locked me out. After that, I learned to treat the seals (after a thorough washing) with Black Majic Tire Wet...squirt some on a small rag and wipe down all the rubber parts. Those seals looked factory new even after 15 years, and no more sticking.
Reminds me, need to apply the BM on my new rig before it starts getting really cold. The BM is also great for any body parts (bumpers, mud flaps, wheel moulding) that you don't want to get wax on. I love the stuff!
Here's a great tip: When you wash the rig, make sure to clean all of the door edge and body surfaces where the seals contact (dirt can build up and hold moisture). And, wax those places too (makes it much easier to keep clean).