>> that I only wanted to spend a month on blows up to a year as I keep going down a rabbit hole to learn new things. And the fact that you are learning new thi

>> that I only wanted to spend a month on blows up to a year as I keep going down a rabbit hole to learn new things. And the fact that you are learning new things, those in themselves are new side projects. So I don't really see you being bad at estimating but the fact that you didn't have all the skills/tech required to pull off the side project. So for the upcoming and existing side projects, why not spend a day or two just coming up with all necessary skills/tech reuqired and re-estimate? - So you have not wasted time as you have still gone ahead and learnt new skills - As others have pointed out, unless there are tangible outcomes you are looking at (new job, revenue, leading to startup) etc, what you are doing it right. Just go with the flow, learn new skills as that or sharpening existing skills are great use cases for side projects! Btw, keep up the great work and it's inspiring to see fellow engineers pursue side projects with dedication.