I see you joined the forum in 2014, and have logged in just 3 ties.
Don't you see how vague your question is, and thus un-answerable?
What does the equipment manufacturer recommend?
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>>IF<< you are asking about how close to the hours predicted by L10 calculations, there are dozens of factors that could make the actual life much longer, or much shorter.
Plus, mythical L10 is a statistically derived number. By definition 90% of bearings will last longer.
If your application is tolerant of downtime, and the machine is inexpensive and spares are kept on hand and easy to replace, then running the machine to failure might be a reasonable strategy.
The point described by L10 life is sometimes described as the initiation of spalling. In some applications it may take 10X longer for the spalling to cause unacceptable running performance.
Using vibration analysis to periodically evaluate the condition of the bearings with the machine running on line can often be used to get the longest life from the bearings and avoid catastrophic failures.
Estimated bearing life varies significantly based on load and speed. Every single bearing, in every different application, will have a different estimated life.
Further, 100 bearings used in the exact same application and service will fail over a range of time, and this is normal. Therefore the most commonly considered "life time" is L10, where 10% of this spread have failed and 90% have not failed. (Then, once you have an understanding of L10 life estimates, you can further explore the multiple real-world factors that can make L10 wildly inaccurate, and the methods to account for those factors too)
You don't need an engineering degree if you want to understand a bit more about bearing life.
