Yes, how long a spell takes to work depends entirely on the spell and how you cast it. A spell that specifies how long it takes can't be perfectly accurate because many different factors go into a spell working, it boils down to every caster is different.
Just like you, your spell work will be unique.
You can take extra steps to try and hurry a spell along. That's not always the best idea though, because it can really complicate and jitter the spell.
What you want to avoid when you first start casting spells is disrupting the process. Once you cast the spell, leave the rest up to nature around you. If you can even, try not thinking about it because until that spell either works or dies off it's still attached you. That energy connecting you to your spell will live on as long as the progress of reality its self.