the 'pump' of a peristalic pump is not the motor or impeller it is the tubing.
if you are running too fast and heating the tubing, it will not draw more fluid.
if your sediment gets imbedded in the tubing, then you need to filter.
I would recomend you check the documentation on the tubing to make sure it is not affected by your liquids and that it is desinted for use in a peristalic pump.
as for life expectancy, that is a trade-off of contaminants and longevigy
and with speed and heat vs. longevity.
if your tubing if fouling with biological growths, then cleaning is required at a frequency faster than the point of fouling.