Because people are so heavy they are gradually destroying the wall-mounted ones.

I'm lobbying my husband that we should raise him to $650 as of January 1.My feeling is that if the tenant's unit is below market, but they're a great tenant, raise it gradually toward market, and consider that you'd probably lose a month if they leave, plus you'd probably have to recondition the unit. 

They also are requesting a gradual rent increase.

Should it be done gradually or all at once??

I figured I would gradually turn my properties over to a property manager, and see how that went... it was fantastic... a professional property manager spends much of their time reviewing applications / interviewing / background checking / collecting rent... they simply apply much more time/experience on the tenant "front end" than I wanted to personally apply.

Buy a small, 2-4 unit multifamily (preferably a quad, but whichever deal you can find is best) that needs repairs, and move from unit to unit fixing it up while you gradually raise rents.

If we need to raise rent we do it gradually so they have plenty of time to make plans, which may include moving. 

I would gradually increase it by $50 at a time.

There are many idiot landlords in Seattle like the guy they mention in the article that are slumlords or guys that raise rent 200% in one month and won't do gradual increases to keep things a little more sane in this market.  

I have been active in KC for around 8 years and I can assure you that taxes have increased very gradually during that time.