Never. I self-relax and I now trim my own hair with the creaclip. I use shears to touch up layers to frame my face.
I've been tempted to go. I visited a salon once in the past year and a half and immediately experienced breakage because they used a lot of heat. I might go back to the salon once I reach my hair goals, but that will be a while (probably 2 years). It is a nice treat if you have a good salon & a good stylist.