When I do stuff for myself I apply the same principles I apply at work. It's insane how easy it is to change stuff later on. Didn't think about this use case before but now you do? Because I have properly maintainable code that is readable its very easy to change and changes are only needed in one place instead of all over the place. Knowledge of the right thing is kept in the right place instead of implicit knowledge all over the code etc.
It also helps to have 'one team be responsible for each service' instead of 'everyone can work on everything'. It's insane how fast you can move if you know the code well and it's maintainable.