| Rank | Factor | Ideal | Remark |
| 1 | Temperature | 70 F | Epson recommends to keep room temperature between 59-77F. Too cold and the ink might be too viscous, too hot and the ink might dry too fast. My personnal experience over the last 4 years is that this is by far the most important factor! |
| 3 | Temperature variation in between use | as small as possible | Thermal expansion and contraction of the ink and head might create problems. |
| 2 | Multiple succesive cleaning, aggressive cleaning | Never | Multiple reports of failed heads after heavy / power cleaning |
| 4 | Humidity | 50% | Epson recommends between 40-60%. The higher the better but molds may be an issue above 60%. |
| 5 | Dust | as little as possible | Use a dust cover! |
| 6 | Usage | print daily | Users report less clogs with higher usage. Personally, I have not noticed this. I print irregularly and I have sometimes no clogs after weeks of inactivity, and sometimes I have clogs in the middle of a stretch of heavy use. |
| 7 | Firmware | latest | Latest FW is HN0126D3 – dated 16-APR-13. Latest FWs includes improve clog prevention features. |
| 8 | Wiper blade/damper /other printer defects | No defects | See Eric's mega long post. |
| 9 | Firmware settings | default | AUTO nozzle check might keep you from printing with clogged nozzles which might damage the head. I've had good luck with the last FW. |
| 10 | Type of paper | least dusty | Some papers produce lots of fine dust: bad! |
| 11 | Time between last print and power down | as soon as possible | Printer makes different noises and potentially has a different shutdown sequence when shutting down immediately after printing vs. an hour later. |
| 12 | Leaving printer on or off | off | OFF keeps the head parked and sealed. The x900s don't seem to wake up regularly from standby to maintain the head. |
| 13 | Ink shake | ? | Epson says: "Remove the new cartridge from the package, shake the ink cartridge at least 15 times horizontally in approximately 5 cm movements". Doing so regularly might introduce air but might keep the ink more homogenous. |
| 14 | Ink age | fresh ink | Potentially, old ink might clog? |
| 15 | Printer age | neither new nor old | Some reports of printer being more susceptible to clogs initially and then improving with usage until wearing off. |
| 16 | Ink quantity | not almost empty | Some reports with more clogs being associated with nearly empty cartridge. |
| 17 | Is printer level | yes | Epson recommends making sure the printer is level. Presumably this makes some sort of difference. (level from left to right and back to front) |
| 18 | printer hardware revision | ? | Are there different hardware revisions? |
| 19 | Max temperature ink cartridge was exposed to. | < 40C | Epson recommends to store ink cartridge below 40C. Presumably, something bad happens at high temperature. Shipping ink in the summer in the Southwest will definitely expose those inks to higher temperature than that. |
| 20 | Printing with clogged nozzles | NO | Does printing with clogged nozzle damage the head? |
| 21 | startup cartridge | NO | Some reports of more clogs occurring with startup cartridges. |
| 22 | Cartridge design revision | Newer | Is there an old and a new cartridge design? |
| 23 | Phase of the moon | not full | Obviously! |