I only drive 3 type of taxi before.....
Solid one is the Crown, drive until scrape, km run 1 round,
meaning 999999.....
Sonata not long.....
Merc cab take over already 600,000km, run 1 round and nearly hit
2nd round 
Merc more troublesome, hit 999999 must go C&C for 1 day
tuning.....rental free.....
Seems like all three brand cars very durable.
If one car travels 350+350 kms=700kms per day, then it would
travel 255,500 kms per year or 1,788,500 kms for 7 years. So
one vehicle could potentially travel 1.75 rounds per
life-cycle.