Reliability vs. Durability:
Reliability is the ability of an item to perform its function under specified conditions over a given period. It is usually expressed in terms of mean time between failures (MTBF), which is the average length of time that a device will operate without failure.
Durability is the ability of an object to withstand physical damage from normal use over a long period. This may include wear and tear, corrosion, impact, etc. In some cases, durability is also referred to as "endurance."
In very simple terms:
A durable product lasts a long time. A reliable product works as required.
When I buy a shirt, I might be looking for a durable shirt. When I buy a car, I might look for a reliable (and durable) car.
In summary, reliability refers to the ability of an object or system to perform its intended function under specified conditions over some defined period of time. Durability refers to the ability of the object or system to endure physical damage from normal use.