How Should I Handle My Future Rate Increase?

If you have regular clients that book frequently, you could message them and tell they you will be raising your rates on X date. If you want to, you can grandfather them in and tell them that you will apply your old rate to their requests for X amount of time. Otherwise, for repeat clients that book infrequently that you want to grandfather in (you don't have to), the next time they book under the new rate just message them that your rates have increased but you will grant them the old rate. Then edit the stay details.

When I increased my rates, I did not have a lot of frequent clients, so when I had a repeat book, I just told them my rates increased but I would apply my old rates to this one stay request. No one complained about the new rate.

Rates are not automatically grandfathered unless your repeat client uses the book again feature. If they create a new booking request your current rates are applied. I'm mostly a walker and have recurring clients so I notified them 30 days in advance of a rate increase. Depending on how many clients you have I would notify them of the rate increase and if it will apply to them or you will adjust at the time of booking.