Until recently, my only pump-up sprayer was a Chapin from the 1990s. I had to recharge it every couple of minutes because it didn't seal well. I had to keep cleaning debris out of the spray tip. The tank was designed so that debris tended to stay in when I rinsed it. The pump didn't work very well and couldn't be disassembled for cleaning. The diaphragm in the valve was often sticky.
A few months ago I bought a second one so I could wash and rinse out of reach of a hose. What a difference! Everything including the pump comes apart without tools! The pickup tube has a strainer! The pump assembly screws into the tank with an O-ring instead of a flat washer. The space around it is an open bowl, so I can use an ounce of water to verify the seal by checking for bubbles. I can come back weeks later and still have pressure!
Why didn't my 1990s sprayer have these features?
An unexpected benefit has been ease and efficiency washing walls, woodwork, and floors indoors. It used to require a wash pan and a rinse pan, to carry around and maybe spill. It meant soaking my hand in cleaning solution, which would get dirty as I worked. If I mix a quart, which could be borax in water, the sprayer can be charged and ready any time I have a minute for a wash job, and I dip my hand only in rinse water.
A standard sprayer nozzle shoots 1/4 gallon a minute in a stream or a cone. Outdoors, it was adequate to rinse a mower but not a car or a wall. I got a kit of flat spray heads: 1/4, 1/3, and 1/2 gallon per minute. It came with a strainer!
The 1/2 gallon flat nozzle works great for flushing a car or truck. If the job takes 3 quarts of rinse water, that's 90 seconds of rinsing -- a few seconds for each section. No getting wet, making puddles, getting the hose out, or putting it away.
I have to use the flat nozzle kit with my old sprayer. It's a Chapin kit, but it doesn't have an adapter to use with my new Chapin sprayer unless I remove the wand.