Really, it’s up to each family and I would only advise to be flexible and watch out for grumpy (don’t forget to eat!). My family:
I went with a 4 months old and 5 years old in july 2015 and never took a midday break. It was an 8 days trip + 1 day where my husband and son went to Legoland and I stayed at the timeshare with the baby. We did leave in late afternoon twice because we were tired.
I went for a 10 days trip in sept-oct 2016 (daughter was 18-19 months old) and still did not took a midday break (unless you count the hurricane that closed the parks a break lol). But again we left early twice.
And we are leaving in less then 2 weeks for a 10 days + 2 water parks days and still not planning any breaks, but we always plan 4 commando style days, one for each park, and the rest are more open to leaving early our a late start.
We take lots of small break, walk slowly, enjoy the theming, etc. We usually plan long indoor attractions and shows in the afternoon as much as possible. If we leave, take a break and come back later, I doubt we would be able to rope drop the next morning too.
And we are also planning TL and direct to DS and T-REX for dinner lol. We will probably just rince off, dry ourselves, change our clothes, throw our bathing suits in a bag and call it good enough.