The crowd that comes to see/hear me often comes to catch up on my family and personal life too, so I am expected to take breaks. I also play mostly dance situations, so the house needs the dance floor to empty every so often for people to head back and order more drinks. A typical 3 hr party for me is 1 hr straight then a 15 min break (with music playing from my system) 45 min on, 15 off, 45 minutes till the end.

If you DO take breaks (and I encourage you to do so), use the time to get to know your clients and what they want to hear - shmooze the crowd, kiss the babies, etc ... it's a sales job. Sell yourself, then play good music.