I have & use 3, small one for chopping nuts, onions, & any small quantities, medium for slicing, chopping, mostly vegetables, large because I can garden produce and salsa in summer. Makes short work when I can 50 or 60 quarts of salsa or stewed tomatoes each year. Not worth the clean up to use large or medium for small jobs, takes too long & too hard on medium size to use for canning so what size depends on what you're going to use it for. The inexpensive ones last just as long as the higher priced ones as long as you use it for what it's intended cause it's the blades that get dull and plastic pieces that wear out or crack first. One usually lasts about 5 years or so for me & by that time they've come out with a better model anyway. Only 2 seniors in this household, one with diabetes so food production and diet have a high priority.