I have been writing programs of varying complexity since I was in the 6th grade, so, call it 39 years. For a portion of that time, call it 14 years, I worked on code that had other people contributing to it. During that, what, 36% percent of my programming life, I learned many lessons that I’ve carried into my solo programming.
Tools, best practices, all kinds of work patterns and code idioms show up in my personal projects not because they’re the most efficient way to get the project done, but because I’ve learned that if I ever do want to collaborate with someone, then that’s made a heck of a lot easier if I do some planning in the beginning. Also, because I love future me, I don’t want to give future me some big pile of spaghetti code with all kinds of undocumented special cases just built in.