Hi Anto, I've been using various refill kits to refill cartridges from Lexmark, Canon and HP printers for the last 12/13 years and refilled my last pair of HP cartridges for just over two years. These printers have print heads on the cartridges so I wouldn't know about Epson printers.
Many cartridges get blocked up through lack of use but a short weekly use of both cartridges should avoid that happening.
If they do dry out then soaking the print head in a saucer of hot (not boiling) water and a wipe with a paper tissue should eventually cure them, repeating if necessary.
I would also add that many printers now have chips in them (or in the cartridges) to prevent you from refilling and re-using but there are ways around that.
If you do try refilling them, then I suggest that you refill them BEFORE they run out otherwise it is possible to burn out the internal heaters of the cartridge which will then always leave a permanent streak in the printout.
Considering that you can get a cartridge refill kit for £1.99 these days, it's not a lot to lose if the results are not acceptable considering the amount of money you can save over the years.
Incidentally, I've never noticed any difference in the colour output of the various kits I have used.