I didn't see an answer to this question after a brief search, so I wanted to ask here.
I got in to an argument with my DM tonight. I assume, from the way unseen servant is worded, that I can have as many as I can cast. E.g. every 10 minutes I can summon another one (as a ritual) and just go to town with them.
The DM focused on the wording of the spell, where it says:
This spell creates AN invisible, mindless, shapeless force
and interpreted this as meaning I could only have 1. I assumed this meant that the spell could only create one at a time, but each casting could create another one.
So, who's right? Based on a lot of what I've read online, it is assumed that people can cast many of these to have fun with them. Does this come down to grammar? Is there some rule that makes this official one way or another?
You can have as many as you can cast
Unseen Servant has no concentration requirement, and no stipulation you can only have one servant at most.
Compare that with Minor Illusion, which explicitly says you can only have one effect up:
Or Simulacrum, which removes the previous clone if it's cast again:
Or Control Flames or Prestidigitation, which puts a limit on the number of effects it can have at a time:
Unseen Servant does not have a clause like this written in it. If the designers wanted you to have at most one servant at a time, they would explicitly say so, in the way they wrote those limits on the other above-mentioned spells.