What is the hydraulic brakes expected life? I bought a pair of hydraulic brakes (Shimano BL-M395) for my MTB. After 8 months (less than 1,000 kms), both (front/rear brake) started to leak oil thru pistons, rendering pads contaminated and the brakes unusable.

Being unserviceable (except for bleeding), the caliper or the whole kit must be replaced in case of problems. That's not cheap.

Thinking about buying a new pair, I wonder How long will last typical consumer level hydraulic brake (years, kms)? It's something you have to discard and replace every year?
Shimano warrants to the original retail purchaser that the Shimano bicycle division product for which they received this warranty, is free from non-conformities in material and workmanship for a period of two years (...)


As you can read in Shimano's North America homepage. So if you bought this new, go there and complain.

Disc brakes with proper maintenance should last for a few good years even on an daily usage basis, and Shimano's are known for their reliability.

If you bought them used or did something you shouldn't (incorrect oil for ex), you can try to get them fixed, but since they're around $35 each, lever and caliper, I'de just buy new ones.