One of a home owners biggest mistakes is to buy an inexpensive roller cover. They typically only have 10 thousand fibers per sq inch. A natural lambskin cover, on the other hand, can have 60 thousand per sq inch. By having more fibers it allows a greater transfer of the paint from the roller tray, meaning better coverage, less time and saves on labour. Also, if you pre-wet a lambskin cover with water first then ring it out it will hold more paint right away. The clean up on lambskin covers is not so bad and while it is more expensive, after painting wash it, store it for years and use it on future home projects. The lambskin cover cost will save you from ever having to buy a cheap, throw away cover, lessens your painting time and saves landfill space.