When I was a kid and I got a new set, I would build it according to the instructions, play with it, and then disassemble it and sort it into my brick collection. Occasionally I would get the instructions back out and re-build it, and other times I would kitbash and make random cool stuff.

My parents still have all my Legos from the 90s, including the instructions, and I've been able to rebuild a bunch of the space ships with translucent neon accents. It's pretty sweet and my kids love it.