Boundaries are wonderful things, they prevent us from going too far when set and used correctly.
We are more likely to respect boundaries put upon us by others than those we impose on ourselves. That is assuming we put any in place to begin with. Just telling ourselves that we will know when enough is enough is not a good way to hold ourselves accountable.
Not only are boundaries a good way to measure things like project limits but they also teach you a useful skill that you can carry through every aspect of your professional career.
Just as important is to share those boundaries with others, they might be project based like deadlines or budget constraints. Or they might be personal ones like hours that you are prepared to work or tasks that you will and will not perform. Sometimes it can be best to think of them as a kind of verbal contract with yourself and others.
Boundaries are also good protection against burn out, one example would be to set a specified amount of time you are going to spend on something and then stop, this might be for an entire project, or it might be a certain amount of hours per week or day. This will stop that urge to keep going and push yourself too far, resulting in abandoning something or delivering a rushed product rather than the quality you know you can provide.
Another example would be the amount of money you put into a venture you are excited to be part of. By specifying a limit of cost ahead of time you can stop yourself from going too far and getting a bad return.
As I mentioned earlier, these boundaries are only as useful as the enforcement you put on them. So next time you approach something, take time to define some boundaries before you start and keep them close for reference.