Stone Tablets and potions?

I have a quick question about using Stone Tablets, and I guess other permanent bonuses as well.

I know I should save them until later on when you have high stats and when the LP cost has gotten pretty expensive. But what about Tablets and potions for skills I’m not using or leveling, or Tablets of health and mana, am I free to just use them when I get them or just save them with the others?

My build is a Dex Bow/1h build if that helps.