I agree with this. Good advice.
There's a bunch of different routes you can take in purchasing a pressure washer for your business, depending on how your business is set up and what types of tools you like to buy.
There are several types of pressure washers on the market. There are the disposable electric units and the disposable gas powered units. These are basically the lower priced units (under $500) that typically have the cheaper, stiff hoses, cheesy plastic wands and aluminum direct drive pump that isn't rebuildable. They come with a parts breakdown with part numbers, but try getting the parts and you'll likely throw the unit in the scrap pile and buy a new one.
Then you have the "industrial grade" units from the box stores and the likes of Home Depot or Lowe's. These units in reality vary from gas powered throw away units up to entry level, less reliable rebuildable units. They are nice units so long as you're not taxing them all day every day. These units can be rebuildable but often will have inferior stainless steel parts that don't really last that long.
Then you have the real industrial grade pressure washers which vary in output pressure and have rebuildable pumps with high quality ceramic and other real high quality build materials. These units have real world parts availability and great engineering and very high reliability. These units typically start at around $2500 and will vary in reliability and function depending on your needs.
If you're going to be a business owner who employs a crew of detailers and spends more time cold calling, crunching numbers, scheduling and basically running the business end of a higher volume operation, it would be wise to invest in a "real" industrial grade unit with a belt driven pump, adjustable unloader, recirculation loop and a built in time out feature that shuts the unit down automatically in the event one of your employees forgets and leaves the unit run when finished with it.
Even with the recirculation loop the pump can still sustain damage if left running for extended periods. If this occurs and causes down time (payroll) and costly parts replacement plus labor and transportation to and from a repair establishment and possible loss of clientele, that money could have bought you another industrial grade unit. It's wise to have a time out feature to protect your investment if you rely on others to care enough to protect your company's assets.
A lot of these high end industrial units have high quality, strong and more user friendly hoses. Some are electric, some are gas powered, some have direct drive pumps and some have belt drive pumps. The belt drive pumps run at a much lower RPM and do not share the heat with the electric motor or the gas engine. Slower RPM and no shared heat equals high reliability, which of course ends in less down time and expensive repairs. It's a "pay now, or pay later" type of decision when making a smart purchase of a pressure washer.
If it's just you doing low volume, non industrial work on your own then I guess a cheap throw away model would fit the bill, but even then it's much easier working with a higher quality, more user friendly and more reliable unit day in and day out.
If I used cheap throw away units, I'd have a back up unit with me at all times. If you use these cheaper throw away units hard at all, over a few years you'll likely exceed the cost of a high quality unit when considering unit replacement costs, driving for those replacements, down time and if you put a price on the annoyance of working with cheaper tools like I do there's even more money out the door.
This is just the way I think, and the longer you're in this field the more likely it will be that someone asks you to do large jobs such as semi trucks, motor homes, large trailers etc. Get a few of these jobs under your belt using a cheesy $200 throw away unit and you'll likely be placing an industrial unit on your wish list.
For "real" high quality pressure washers, I'd recommend looking at the likes of "Landa" or "Alkota", "Karcher" also has a "real" high quality line of pressure washers that you'll never see at a hardware store or box store.
My 2 cents on pressure washers.
