Why Use "Throw-away" Brushes ?
"Greener" - Environmentally friendly
Throw-away brushes are not a wasteful use of resources. There are times when using oil based paints where it makes sense not to wash out the brush - thus creating hazardous waste (in the cleaning solvent itself), which must be managed. It is actually "greener" to let the material harden in the brush after using and to throw it away.
Labor saving
Cleaning out a brush can take fifteen minutes or so to do it properly. If a brush can be purchased for $2.00, why spend $7.00 in labor to clean it? Especially if you are paying an employee to do the cleaning?
When touching up
If you are doing a final "punch list" touch up, you often will be dealing with a multitude of colors with a multitude of brushes being used for these colors, which are left out all day long and by the end of the day the brushes (maybe half of them) are already hardened and probably not worth the effort to clean out.
Linzer brushes are just right for many painting jobs. Are you working with oil based or shellac primers? Or do you need a "throw away" brush - that you don't want to take the time to clean up because it would require solvent cleaning?
Linzer brushes are priced right for Diy'ers and professionals who need a economical brush that can get the job done.
Linzer roller covers are value priced so that cleaning them out is optional. Save expensive labor time required for clean up.