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).