For me, a lot of my side projects are either the result of realizing a tool I'd like to use doesn't currently exist, or something I get excited about while throwing ideas around with friends. The latter typically leads to silly web games or programmatic jokes more often than actually useful things, but I enjoy the creativity that comes with that even if it's unlikely to go anywhere.
I'd rather build for the short-term and if something gains traction, start thinking more long-term, but I'm sure there's other people who really enjoy planning out large projects and implementing them.
The first 80% of the work is the fun part, and sometimes I have to pressure myself to do the last 20%.
This, really. Most of the time you're building something because it doesn't exist already and you have the skill to do it. There are plenty of things that don't exist that really should - and it's bizarre that they don't.
The other option is to save money. Frequently I think about whether I should buy expensive widget X to do what I want. Then I wonder how I could build it myself for less (same with software, but usually finding an open source solution).
I'd rather build for the short-term and if something gains traction, start thinking more long-term, but I'm sure there's other people who really enjoy planning out large projects and implementing them.
The first 80% of the work is the fun part, and sometimes I have to pressure myself to do the last 20%.