Yes, we are very selective when it comes to cleaning. We are higher than most, but when they see what they are paying for, we usually get the contract.
As far has how many times in a year, that depends on the garage and ones budget. Some garages we clean quarterly. Their surface comes out like new. Others are once a year. Their surface looks like new for a month or so. The more oil retraction we can do, the better the long term results.
We see allot of garage cleaning companies out there. Some just power wash, cleaning sq yard by sq yard. I call that a glorified rinse job, not a deep cleaning. For it to be a deep cleaning, every square inch needs to be cleaned with 4,000+ psi with at least 220-230 at the end of the wand. Not 220 degrees at the exit point of the boiler as some do. That number means nothing to me, and should mean similar to everyone else. You want to know what's the temperture at the tip of the nozzle. What is the temperature hitting the ground? That temperture could be different anywhere from 20 to 70 degrees depending on the outside temperature, the quality of the hose, the diameter of the hose and the length. Also if the boiler is shutting off, then coming on again and again.