It seems that wherever you are, there is always someone or people out there who are seeking or in need of someone to help to them. And while it is easy to say yes at times, one has to wary of how much one can offer and how effective you can be in helping them out.
As you may find that you may be biting more than you can chew, nonetheless, they need all the help they can get right? The answer is yes and no, and only you are really the best judge as to how helpful you can or may be to someone and/or group. As it depends on your skills, capabilities and the type of help that is being asked or seems that you are able to offer them.
What I have found that sometimes, although difficult, is that sometimes you just have to say 'no'. Now saying 'no' is not always easy, as the causes, initiatives and projects out there can seem so worthy, yet what I have come to realise is that you can't do it all. Sometimes saying 'no', just as you need to go beyond the sake of doing something for the sake of doing something, and doing nothing for them may allow them to instead find someone perhaps more appropriate (not that you aren't but you may not as readily available or committed as they require).
For yourself, judging too many things can become difficult, you may find too many things clashing and you're being unable to make commitments here in there, needing to sacrifice things here and there and potentially finding that you've burnt candles at both ends which may lead you to burn out - something you'll need to be very careful of.
When you realise and/or know that you're starting to loss your effectiveness then sometimes you may find you may need to take a breather. It's almost like taking a holiday from work/ study at times, particularly since you may find that you can't help others until you've helped yourself. So if you're burnt out, then it's very difficult to help yourself let alone others. The only solution for that is rest.
Anyways, essentially what I wanted to say was that you need to be mindful of what you may want to support and help out with, sometimes it's best to say no. And since there are so many possible initiatives and projects out there to support you need to find the one that fits your skillset, knowledge and interests best. Prioritise, sometimes try out and see what you like best and make whatever you do worthwhile and focused!
I will leave you will another one of my favourite quotes, and it refers to understanding that while we all would love to do everything in life, we can only really do some. But you can focus on certain things at a time then change them, just not all at once.
"Experience suggest that while you cannot do everything, we can always do something" - Douglas J. Soccio