In the old days with one burner and 2 pots it took up to 8 hours for a 5 gallon batch. Now with my 3-tiered system I do 10 gallon batches in 5-6 hours. But I really don't pay much attention to the time, brewing is fun and relaxing, it's my quiet time alone in the garage so I'm usually not in a hurry. But it also depends on what I'm brewing. Sparging a beer with a very high percentage of oats, rye or wheat takes longer, even with rice hulls. Sparging a 10 gallon batch of Imperial stout or Belgian quad with 35+ pounds of grain in the mash tun takes a while, you just can't get in a hurry.