When you get your real estate license they tell you that weekends and nights will be part of the deal. After years in the business you can alter these days/times.
The best way to keep clientele is to answer your phone/texts/emails. I am on vacation, and have had two clients call, and answered both. They feel more important when you do. Granted, sometimes on vacation you are not able to do so, but sure nice when you can.
Usually when I leave town, I put a message on my phone, but did not this time, as my deals were closed and had a few things coming up, but they knew I was planning on going on vacation. They were good with waiting until I return from vacation.
Simple statement - let your clientele know they are important, and can call anytime they need you! (within business hours of course)