The spotless wash works well enough at my local coin-op wash that I have no problem leaving it like that until I can really wash it. The water spotting is usually very minor and not permanent as long as you make sure to wash most of the washing water off with the spotless rinse (I hope that makes sense.) The spotless rinse lets only enough water out to wash the washing water off; it takes at least 1.5 minutes to fill up one of my buckets with it. IME the spotless rinse works well enough to last until the next hand wash. Also, in case you are new at power washing, make sure you use the low pressure wash before anything else! going straight to pressure washing will grind the dirt into your paint at high speeds, causing marring.