GWS IPS Motors on LiPo's--2 or 3 cells ?
What really kills your IPS motors is current and heat.
The 2 or 3 cell decision should be based up pilot skill level and power system setup. Using good throttle management and a heatsink, if needed, can extend the life of your motor as you push it to the limit for short bursts.
Depending upon the model, I may use 2 or 3 cells. The gear ratio and prop size also affect the current draw at full throttle and cruising speed.
In general, my IPS motors do not burn out. Although inexpensive, you still need to change them manually so it takes time.
I would make small changes at a time and get a balance in which you don't burn up the motor often but still have the power you desire. Usually, this can be done on 2 cells with a lower gear ratio and prop size. Use 3-cells on higher gear ratios and never exceed 2amps for mor than 10 seconds.
Good luck!