I'm not a maintenance man, but I'm pretty sure you are safe. We use to run a lot of glass filled Teflon...wide open with the first Hardinge 42 Conquest Super Precision lathe we bought. It is still running at a sister company. Never had a spindle repair of any kind in the approximate 12 years we had it. Of course, I am not aware of its maintenance record since the lathe got moved to the sister company about 8 years ago.
However, we have 3 Daewoo Lynx lathes that have all had their spindle bearings replaced. They are around 8 years old. My personal opinion is that it wasn't due to any chatter from machining, but by having guides with too much clearance. Three-four feet of bar whipping can do some damage! We have extensions on the spindles so we can run 4 foot bars.
Our one Daewoo barfeed with chuck (rest have collets) has had a service man in twice to line up the spindle. (No bearings replaced.) Again because of bar whip in the spindle. It has Live Tooling and the spindle doesn't have to be very far off before it won't run.
Don't step on a $20 bill to pick up a penny. Use correct size guides!