Most of the time it's good to put others before yourself, as for most people this brings happiness and satisfaction from knowing someone else has benefited from your efforts. However there are certain situations in which you simply have to draw the line and put yourself first; you are in charge of your life and it's up to you to keep yourself safe and happy. Other people can help you but no-one can do it for you.
Helping others can create good personal relationship with them. Also in the need of your own help, you may get those people to help you. Helping each other wouldn't hurt anybody and it's a great way to be in a community. It shows kindness and sense of teamwork within the group.