I've put out the hummingbird feeders and they do come around but I decided to try flowers instead. They are still coming and they stop at several places on the deck. I found I couldn't keep the feeders either full or if several days went by, clean. They get grungy looking. When I took them down to clean them, there would be mold. It gets very hot here. I often wondered if the sugar water fermented and if it were hazardous to the hummers.
Yes, the sugar water will ferment and it can harm your hummers. You have to keep your feeders clean and the nectar fresh.
If you live in a hot climate you should change the nectar in your feeders at least every other day.
If you have a lot of hummers, like I do, you won't have to worry about the nectar fermenting because it will be gone in about 30 minutes!
But if you don't live in a warm climate or have a lot of hummers, just fill the feeder 1/4 to 1/2 full and watch to see if the nectar is disappearing.
Hang feeders near trees in shady areas.
Try to get a feeder that has perches. They feel more comfortable with a perch.