English Portuguese (Brazil)
Quitting
If you've found you've over-committed or decide volunteering isn't for you, that's OK. You don't need to be embarrassed that you can't contribute further. Contributors will not make you feel bad about it either. Realize that lots of contributors come and go every day. Being busy with your day job or not having enough free time is a perfectly valid reason for not being able to contribute. It's even possible that you might not feel a good fit with the team or organization. You're entitled to offer help as a volunteer how you want and when you want.
First and foremost, though, don't just vanish. When a contributor or potential contributor agrees to do work, can't follow through for a valid reason, and vanishes, the team may not know the work can be reassigned. In some cases, people in the team may even worry about the contributor's health or well being.
When you've decided it's time for you to go or take a break, let your sponsor or the list know and let them know what you were working on. Having people think you are working on something when you aren't slows the team down, and ultimately doesn't benefit you or the team.