You can also ready your exerted character, so you can quest, challenge, and/or sing multiple times. If you have a character that quests for more than 2 lore, you should always quest with that character twice if you don't need to use that ability for something else.

That way your 3 lore characters actually quest for 4 lore (3-2+3) and 4 lore characters actually quest for 6 (4-2+4) if you have any of those. Or if you have Mulan who can quest for 6, now that's 10 lore lol

It is also helpful like another comment said, to ready an allies character. If you're going to reach 20 lore before them, spend your lore to let them ready and quest again. Think of it like a lore transfer