There are four contributing factors to pump reliability. If you get all of the factors as close to correct as you can, the life of your pumping equipment will be optimized.
Firstly, there is pump selection. You require a correctly sized pump that will continue to do the job for the long term. You can save some costs initially by installing an incorrect or undersized pump that will manage to do the job but it will not be a good investment long term because the life of the pump will be shortened due to the additional stresses on the equipment maintaining the required performance.
Secondly, there is pump installation. There are two important parts of any pump installation and they are the base or plinth that the pump and motor sit on and the alignment between the pump and motor. Having a good solid base for the components to sit on is important so that there is no movement after installation causing misalignment. The alignment between the pump and motor is critical to ensure the maximum life of components such as bearings.
Thirdly, there is pump operation. For example, the pump must never be starved of the fluid or product that it is pumping because this can reduce lubrication and cause overheating and that can have catastrophic consequences for internal components such as mechanical seal and bearings.
Finally, there is maintenance and repair. Ensure that you use the correct fluids when servicing and check the fluids for contamination which could be an indicator of another problem. Also, use the correct spare parts that are right for the job. There are a variety of materials used in mechanical seals for example which are suitable for different purposes.
Get all these factors right and you can expect the maximum life from your pumping equipment.