How long is a piece of string? There isn’t an exact answer for this, due to the sheer number of variables in bicycle bearing use. Between bearing brand, bearing type, riding environment and bike maintenance schedules, there is so much more to factor in than just bearing material. 
With that in mind, if good new bearings do wear quickly, there is a chance they were wrongly adjusted or that seals have loosened. If bearings have worn too quickly without either of these factors, we recommend considering another brand.
If longevity is what you’re after, good quality steel bearings may last longer than full ceramic or hybrid bearings if the bearings experience any shock loading. By nature, ceramic balls are much harder than steel and have much lower elasticity. This means that sudden impacts, with hybrid bearings, are much more likely to result in dented raceways.

Our determination to remain specialised gives us a high level of product knowledge, providing bearing and lubrication solutions to existing or potential customers, whether individuals or large corporations. We don’t just sell bearings, we help to solve your problems. - Chris Johnson, managing director of SMB Bearings.