I don't know is the answer. The bearing type number might help. It's possible the bearing is self-lubricating, broadly meaning it will run satisfactorily for thousands of hours and then have to be replaced. Mini-lathe bearings aren't heavily loaded as bearings go, so probably OK for several years. They're not like the plain bearings found in most older lathes, that require a constant oil feed.
Judging by the absence of complaints on the web, bearing failure isn't a common mini-lathe problem. But people do replace them, partly because inexpensive ball bearings run a bit rough (and get worse), and partly because taper bearings are more suited to lathe stresses.
I think the most important thing to avoid is over packing the bearings with grease. Ever unreliable "Common Sense" says more grease the better, but too much grease is a really good way of wrecking bearings. So, if it worries you, put a smidge of grease in and check periodically.
I don't worry about ball bearings unless they slide front-back or lift up-down, make lots of noise, or get hot.
It's a mini-lathe, not a Swiss watch!
Dave