Highest I've ever been is 8,000 and that was only to get over some weather. I've been higher in a glider. My default height is 3,000 and a bit. The bit is because everyone else tends to fly with the big hand at 12 o clock or 6 o clock so I reckon, probably wrongly, that I'm giving myself a bit of risk reduction.
In the summer I don't like getting chucked around in the mid afternoon boomers so I tend to head off to six or seven thousand for some quiet air and good vis.