I've learned and limit myself to 3 builds at a time. I used to do the chassis/interior and be done way before the body, then rush the body to finish to the detriment of the project. Now I start on the body first and only when it's near ready for paint do I start on the other bits. Works for me, but like mentioned above, if you're happy with 100 projects going then by all means. IT'S A HOBBY!