If your personal project is small and self-contained enough that you write it once and then you're done, then sure. My projects tend to be much larger, and be works-in-progress. As annoying as it is, taking the time to plod along and do proper testing has saved me time and time again. If you only have a few hours a week to work on a project, the last thing you want to do is spend 8 hours (AKA 3 weeks) figuring out why something isn't working.
Really depends on the size yeah. If you're working on some 20k+ code megaproject then it makes perfect sense, but for the average small side project I feel like the code and approaches change so quickly that you'd just spend half your time rewriting and fixing broken tests for no real gain.
Hmm, well my "small recent" project, that I got to my own personal MVP standards, is already at 2.6k lines of code; and my long-term project is at 9.4k lines of code -- not counting the little side libraries where I put more generic code I thought might be useful elsewhere. So, I guess you're not too far off.
That's why I gave this talk: intuition says that writing tests for personal projects would slow you down and make you less productive.
But I've found the opposite to be true! My capacity for personal projects dramatically increased after I started habitually writing tests for them.
It turns out tests aren't just useful for large projects with multiple contributors: they enable horizontal scale for small projects with a single contributor too.
As someone who doesn't do this as much as I should, I agree.
On projects that are well covered with tests, I find I'm less afraid to pick it back up again and start working on it, because I know there is less chance of some missing context I had in my head months ago and now is forgotten and my change will break the app.
Most of my small projects have automated deploys using ansible, not because I couldn't do the deploy manually (in most cases it's ssh to the server, git pull, run migrations, collect static, restart the server), but because with ansible I don't need to remember the manual steps.
I am sorely lacking in the documentation area tho :-) Your post prompted me to try to improve there, as I can definitely see the benefit.
I suppose it depends on what you're trying to do, but the thing about personal projects is that you don't have to maintain them :P