I play with my toys and I keep them loaded. And if the springs should weaken later, then so be it. I'm not that fussed by it. If I was worried about keeping my toys in minty fresh condition, I'd never open them.

While I always take care with my toys when I play with them, I do expect that some reasonable level of wear will occur, and the weakening of springs is something I consider reasonable. What's the worst that could happen if the springs weaken? They'll become just like original G1 launchers that I grew up with as a kid, and I'll just have to "manually" launch them! No big deal.