Not always, as Robert ven der Elst mentioned earlier, this might be overkill for a little app to use big CSS frameworks like bootstrap or foundation.
Instead i just use a simpler one, called Skeleton : getskeleton.com Just a css file that give some basic styling for buttons, forms, typo, tables and lists, but also a grid. I think this is a good starter for simple project, if you do not have time to create yours :)