Nuisance rent raises.. are they worth it??

[Joe Ebanks]

Hi guys, I am new to the landlording thing. I have 7 units now and they've all been very successful. almost no vacancy. I read hear and in books about how you should always raise the rent each year. I tend to agree because of inflation. 

However if you have very good tenants, and you are already basically charging market price for the rent, I think you may annoy your tenants over time to actually find a new cheaper rental. 

Curious what the thoughts are on this, do you ALWAYS raise your rent by 1-3%, or are some of you just keeping it the same on your quality tenants that you have very little problems with ?