Depending on where you live.... I'd say put one up.

If none come to it within 5-7 days (shorter if really hot out), I'd change the solution, as it goes bad quickly. Mold kills hummers.

Ours just left, last week. I had two regulars all summer and they even returned after we came back from vacation (I had taken the feeder down for the 5 weeks.).

I read an article recently in a science magazine, that hummers have a very good memory. They return to old feeding spots, over and over. Some birds may be flying South now, so if you are in a colder region, your bird may just be temporary.

I find they are also attracted by outdoor flags. This is how we get them to stay around here. We have a flag in the back and front of our home. Nice for us to look at, but I think it draws them in. Flags certainly were a factor upNorth where we are in a remote area with no flowers. Hummers eat alot of insects.
I visited a bird refuge in Maine one summer, and they had scads of hummer info. Nectar and sugar water are not their real foods you know. They eat alot of black flies, and often steal bugs out of spider webs.