Every 2 hours (daytime) until 10 months. Then he'd go 3ish. And we were doing 1-2 overnight feeds until 9 months. Then 0-1 until 15 months when he weaned.
DS just turned 8 months over the weekend. He has consistently eaten 5-6 oz every 3 hours during the day since 3 months, with the exception if he takes a really long afternoon nap, he'll go 3.5-4 hours. He's been eating solids since 6.5 months, and the formula intake hasn't decreased or spaced out at all.
E eats every 3-3.5 hours or except at night and he's 4 months. He still takes 4oz bottles right now but we've been thinking about upping it to 6 and see what happens. Last time we gave him more he spit it up but maybe it will work now!