I started last year with 5 gallon batches then switched to making a few 2.5 gallon batches and brewed my first three 1 gallon batches last week. I can brew then on the downstairs stove in about 3 hours and I can experiment with them. I am currently trying out a few recipes for a good, light, summer beer and I don't want to have to make 2.5 or 5 gallons at a time! I think 1 gallon batches make you appreciate what little good beer you made, bit also allows for much more variety.