I have an Epson 7890. I live in Sarasota, Fla. The A/C runs often, as you can imagine. I print at least a few times a week. The relative humidity in the house is usually around 30%. I print a nozzle check before a printing session. Oddly, I have found that if the nozzle check shows some blockage, I'll print out a color patch about 6 X 6 onto photo paper. Sometimes I'll have to repeat the process one or two more times. 90% this fixes the problem. I avoid head cleaning, as it is a destructive process. It's hard on the heads. The 7890 doesn't clog nearly as much as the 9900 I had. The head on the 9900 died after three years. I sold the machine on eBay and opted to dispense with orange and green.