I really value tests on projects I work on alone because the work is usually intermittent. I don't have the time or energy to deal with regressions, and I may not remember everything about the system by the next time I work on it.
I also find manually testing to be tedious, so I'd rather spend that time writing code that does it for me.
I also find manually testing to be tedious, so I'd rather spend that time writing code that does it for me.