As long as you maintain the engine properly and change the engine oil and oil filter every 3,000 to 5,000 miles and don' run the engine low on oil then the engine main and rod bearings should last the life of the car or other vehicle they are in.
Also if you continue to race the engine or rev the engine before it has enough time to warm up and lubricate the engine then the bearings can sometimes be starved of engine oil which could cause them to run dry and then you can have a spun rod bearing or bad worn out main engine bearing.
When starting your car or other vehicle allow the engine to idle for at least 1 minute and then slowly take off and after a few minutes then you can accelerate.
Doing that allows the engine to bring the oil up to temp so that the oil flows more freely through the engine.
Main and rod engine bearings usually fail due to failing to change the oil and oil filter when needed which causes poor lubrication to the engine bearings and also racing the engine.
Or if you run the engine dry on oil or low on oil the bearings can't get enough oil to properly lubricate them and then the engines bearings fail due to friction.