I don't know what spare parts you might need, you could just wait until something fails and then buy a couple of those parts, that would save buying parts you might never use.
On the clean up side of things, how long is it taking you to clean up now? what paints are you using, oil based or water based?
I only spray water based paint through my Titan and clean up is a doddle, I just fill a 40lt tub with water (warm water if I'm lucky) set the pump to Turbo clean and let it get on with it, gives me time to have a smoke, cup of tea and a couple of chockie biscuits. :Thumbs:
The gun and tips I just stick in a tub of water and clean that at home, hot water and a tooth brush (usually the wife's, but don't tell her

) a few minutes with the brush and its clean.
The main unit I only clean the outside of it every couple of weeks, I've found if I give it a good spray with WD40 the over spray it gets on it doesn't stick much.