Homeward Bones

I am relatively new to DS and curious how people generally use these. For instance I am going through Sen's Fortress and having a rough time, I probably lost enough souls to level up a few times. I was wondering if once I have enough souls for 1-2 level ups, it is OK to use a homeward bone and go back to the bonfire to level up instead of pushing forward and risking losing the souls. Or should I be saving the bones for a more valuable use?