I have been a landlord for just over a year now. I have not raised the rent from what the other owner charged. I have thought about, but I live in my building and I'm not in it for a big profit just looking to have a nice place to live thats not going to cost me alot over the long haul. If I did I would have many good reasons for doing so. Since I bought the place I have been working to fix it up. I have establised a nice lawn, improved the electrical and plumbing. installed a new more reliable heating system, painted outside and more. plus the proberty taxes have gone up as well as the cost of natural gas for heating both which are costs the rent for any property has to cover.
If I were to raise the rent I would be justified because the cost of running the place has gone up and I have made improvements to make it a nicer more livable place, so that its worth more.

I think it has always been a 3 month notice for us...before the signing of a new lease.

on a month to month lease 30 days would be the minimum required unless the state you are in has different laws. I would give 2-3 months notice so that tenants can prepair to put the larger rent in to their budjet.

We get about 1-2 months. We're on month-to-month. It goes up about the same time each year....glad we're getting ready to buy a house!