They fit exactly the same printers — the XL simply holds more ink. If you print often, 502XL works out cheaper per page and means fewer cartridge changes. For light use the standard 502 may be enough. You can run one of each in the same printer without any problem.

Both numbers appear against some of the same machines because Epson used different cartridge numbering in different regions. For a UK printer, go by the number printed on the cartridge currently in the machine — that is always the reliable guide.

No. The 502XL range uses separate cartridges for each colour, so you only replace the one that has actually run out. A multipack normally works out cheaper than buying four singles, so it's worth a full set if you print regularly in colour.

Yes. Refilling is the cheapest way to keep a XP-5100 or WF-2860DWF running, and it keeps empty cartridges out of the bin. There is an added cost to refilling these cartridges, you need to purchase a chip resetter which would cost an additional £25 approximately. We dont currently sell these.