Every sprayer I get lasts about two uses. I must be doing something bad wrong. I even wash them out after each use and the next time it still won't spray right. How do you keep a sprayer with weed killer in it without clogging up the sprayer???
Buy a better sprayer. I just got my second Solo 4 gal. backpack sprayer last week. The first one lasted about 7 years, actually, it just needs the diaphragm rebuilt and it will be as good as new. My new one is a piston pump. Less to go wrong.