With all due respect, I completely disagree with the above. I have cleaned the gutters on over 3000 houses/buildings, and I have yet to use a power washer to do it.
You are being paid to make them functional, and no more. No one cares if you can eat out of the inside of the gutter or not. Clean them out pretty good, but be certain that the downspouts are clear......that is critical. While this would certainly be easier with a power washer, its not necessary. And with all the time it would take you to drag hoses around these buildings, me and my crew would be half way done the next complex before you finished this one.
I do run some water down the downspouts, but I almost never flush the entire gutter, with a few exceptions at the owner's request.
There is great money in the complexes, but some of them are cheap as can be and you will never be able to price them low enough. We have a 59 unit townhouse complex we do which I charge about half of the amount per unit as I would if I got called out to do just one house.
When cleaning gutters, alwasys start at the downspout........for two reasons. 1) If there is not too much debris in the gutter, it will all be washed down towards the spout, and you will only have to go up once. 2) If the gutter happens to be full of water, you can unplug the downspout and let the majority of it drain prior to cleaning the rest of the gutter = less mess.
When you pull the debris out of the gutter, grab a handful, pick it up, but pick it up over the first row of shingles. By doing that, any loose debris will drop on the shingles and not fall down onto whatever is below you, and will not drip nasty stuff down the face of the gutter. Just make sure you clean off the shingles then............I usually get the bulk of the stuff out of the gutter, then sweep (with my hand) the leftovers on the shingles into the gutter..........then do a final sweep with my hand in the gutter.
I have an under 1% call back rate doing it this way. We get them clean enough, and do it right the first time.
I do not haul away debris.........we can almost always find somewhere to dump it on-site so it will degrade. I very rarely take leaves with me. At single homes, if there is no appropriate place to dump them, I bag them and leave them for the trash. If the homeowner is home, I ask them if they would like me to put them by the curb..........
I have never had complaints about doing it this way.
Pricing...............price the complexes as cheap as you think you can do them and still be profitable. I've been doing this a very long time, I can just eyeball a gutter job and price it out. It's really hard to explain and just something you'll get used to over time.
Look at the building and imagine it were a house. Is it as hard as say, two houses? Three? Do some multiplication and come up with a price, then discount it some for volume. The more buildings, the larger the discount.
Lastly, most complexes will require you to add them as an additonal insured on your policy......and have a certificate sent to them. If you get the job without them asking for the certificate, there's a good chance their accounting department won't even pay you until they have it in hand.
Bid on these jobs early.......most of them give the contracts out in late summer in preparation for fall. Some of our complexes have them done twice per year, but some of them just do it in the fall. We have one that does once in the Spring, and TWICE in the fall. I love that one.
Anyway, good luck to you.