Should I flip or rotate this mattress?

Rotate it, do not flip it. This is a one-sided tight-top mattress, so only the top surface is built for sleeping, which one reviewer noted as a trade-off versus older reversible beds. Turn it head-to-foot every few months to spread wear and slow body impressions. This matters here because durability is the softest score at 6.4 out of 10, driven by the comfort foam; the heavy-gauge coil core itself resists sag well.