Every time you use the system, flush the sprayer, hose, and gun out with water when you finish painting. Since these systems only use water-based paints, keeping them clean couldn't be simpler! Put the tips in a jar of Titan's Tip Clean to keep them ready for your next job.
Why upgrade to the Caster Wheel? Time. Although the 850 has a turnable front wheel, it's a manual pull-pin, which requires you to stop painting, go to the front of the machine, and adjust the pin, then go back to the machine and start painting the lines again. With the cable caster, it works like brakes on a mountain bike - squeeze from the handlebar and turn on the fly.