I believe I experienced this with my Prelude. I probably did with my Accord. I remember taking off the panels because the upholstery was falling off, but I hit an elk before I was able to fix that. I have removed the panels a couple of times in my Civic, they were cracked the first time, and taking them on and off has only made them worse.
I think the Arizona heat is especially rough on plastic.
When I fixed my window, a piece of plastic fell off. I epoxied it back and it simply fell off again the other day. I thought the only actual fix was replacing the panels, but all of the ones that I see cost hundreds of dollars, although I do not have any idea how to search for them on car-part.com. The plastic seems to be cracking further while mounted. This guy:
Cracked Door Panel Repair / Reinforcement | ClubCivic.com - Your Online Civic Community
recommends using this stuff:
SEM 39747 Multi Purpose Panel Adhesive Dual Mix Cartridge 207ml | eBay
Leave it alone? Is there some cheaper alternative? Is that product or something similar available in larger quantities? Thanks!