You’ve cast your single spell for the day and combat breaks out again. How do you spend your turns?
Throw darts / daggers. Having a decent dexterity you had similar odds as the fighter to hit and do some damage.
Provide light.
Keep watch.
Bind wounds.
Know things about magic.
Discuss plans and observations.
Poke things with a stick (staff).
Ask pertinent questions.
Throw rocks to attack, distract, investigate, sound out.
Pull the rope to close the door, open the door, activate the trap, deactivate the trap, get Smedley out of the trap (again).
Write things down since you're often the only literate character.
Draw maps and make notes since you have a book and it's going to take four more adventures (levels) to come close to filling it.
Remind people to look up. (People never look up...)
Feed people healing potions.
Help the ranger make healing potions (I'm an apprentice alchemist, just blanche the herbs, right?)
Help the thief with a scam (Where is my niece, have you seen her?)
Help the bard with a bigger scam (Make way for the ambassador!)
Help the cleric put a ghost to rest (Ring the bell three times when you say Abermelin? Got it! I minored in Ritualism at the guild.)
Pour your wineskin on the fighter to free them from the viscid globs, obscure color mold, strange phasing tentacle. (My favorite vintage! I weep.) (Or, vinegar; either water or an 8% strength solution of ethanol, acetic acid, or other substances)
Plus other stuff.
Oh,
hell, yes - chief wardog wrangler. Best money you spend.