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Read our primer articles on Grease Guns and Oil Sight Glasses.

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Perhaps I did not get your point in question.

the question is not if you "can avoid" relubrication, but "for how long"
You can, but keep monitoring and get an equivalent product for when you see temperature and vibration climbing. Don't wait for the damage. There are many other possibilities to enable to run for veeeery long without rebuild.

Please write back if I misundestood you.
Dear Robert,

I would tend to agree with macabf, about this.

If the motor is large enough to rebuild, it's large enough to be in the proactive or predictive maintenance program.

I have been working in the industrial world for more than 35 years. The word forever and never do not in my experience apply to anything on a machine. Mean Time Between Failure (MTBF), L-10 and L-50 life are much more appropriate.
I tend to be suspicious of those who use words forever and never.
Start with the motor manufacturer.

Ask Why and Why not and then Listen.

Good Luck.
In general the decision to regrease or not has more to do with the speed, size, configuration (sealed/shield/open), temperature, run-time (continuous/intermittent) than the grease type.

D*N = Diameter of bearing bore in mm * Speed in rpm.

Below D*N = 80,000, lube lasts so long that lubricated for life configuration can be used. Sealed or double shielded.

80 - 120k = gray area.

Above 120k, normally requires relubrication for continuous operation, especially as get up toward 200,000, and continuous applications and high temperatures. If not, grease life will probably be the limiting factor between equipment teardown for bearing replacement.

Above based on info from Heinz Bloch and Forsthoffer.

The type of grease may have some bearing on the equation as well, but I wouldn't trust claims from a salesman without data to back it up.
The rep may have told you that because overgreasing can be as bad or worse than insufficient greasing. If the bearing volume is more than 1/3 full, internal friction results in excessive heat. Overgreasing can also blow out the seal. Relube at the recommended interval, WITH THE PROPER AMOUNT. Lube Techs who ascribe to the "more is always better" approach should be counselled. If that doesn't have the desired impact, the next step is to kill them and eat them. I find you rarely need to take the second step more than once.
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