This is really important to get right. There's a balance as you want to avoid introducing crap but a little restraint and wider awareness makes a huge differenc

This is really important to get right. There's a balance as you want to avoid introducing crap but a little restraint and wider awareness makes a huge difference. I recall being significantly put off after making my first significant contribution online to a non-trivial repo. I was a volunteer and had been making various very modest contributions (ie simple fixes) along with efforts around docs and answering questions from users. A major contributor was known for being cantankerous. He knew what I was bringing in general, and seemed grateful yet didn't hold off with pretty forceful feedback on my first attempt at something more substantial - I had taken a day off to get it in good shape, I knew it was solving something with broad use (ie not just for me!). There were a litany of points. I fixed several but each time there would be more, it was like water on Gremlins! I gave up and stood back for a bit. Ironically it would have been trivial for him to take the code in but it sat forever and the whole thing was a waste of time but I guess I learned a few things! I try to encourage standards but not officiously!