Best way to handle buildings and POIs?

Can anyone give me guidance with respect to when I should be creating buildings? Versus simply dropping POI nodes on noteworthy locations? Creating buildings seems like it could get out of hand pretty quickly.

I added buildings last of all and only then the “significant” ones. Without aerial photos it is too hard as my satnav isn’t good enough to get a good trace of the outline of a building if I walked round it.

But yes, it does get out of hand!