Does anyone keep their WAX type columns isothermally at 150degC and above?

If so how stable is it (in terms of retention) over time?

I am looking for it to share an oven with a packed column operating constantly at 175degC.

For one, use great oxygen traps. Use a stabilized wax column, don't get cheap. I'll assume wax column is installed in the rear so simply removing it after use isn't as straightforward.

From experience and quite hard use, Carbowax columns from two major suppliers would last 6mo to a year at that temperature.

Water samples were repeatedly injected over this time at 40°C and brought up to 180°C and held for 30 min.

I hope this is helpful.