There are factors to consider:
Young kids (7 and under?) - I would always advise that you take the break- EVERYDAY - kids need some 'down time', parents REALLY NEED some 'down time'!!! It is soooo obvious after dinner in any of the parks exactly who DID NOT take the break....tired, cranky kids, not having any fun and tired, cranky parents who are cursing under their breath something along the line of:"these kids are so ungrateful" and/or "we never should have taken these brats to WDW", etc. I swear we see this type of scene EVERY SINGLE NIGHT!!! THIS IS SO SAD, especially when, for the most part, those meltdown scenes would be history - all by a little break from the parks!!
So many people are of the mentality that they WILL have a great time only by being in the theme parks at every possible moment!! WRONG! WRONG! WRONG! WDW must be taken in small doses - yes, you MIGHT miss 1 or 2 attractions, etc. but there is NO COMPARISON for what you GAIN by taking the break!!! If is's only adults, older kids, teens, etc. then of course that depends on the individuals.
Weather - BIG factor - That Fla. heat and humidity sucks the life out of most people in about 3 hours!!! For that reason, our schedule is ALWAYS something like this:
AK (9am - 12pm), Pop Century (1pm - 4pm), O'Hana (5:15 - 6:45) MK (7 - ?)
Best to tour in the morning, best to be in the pool or air. cond. room for most of the afternoon, best to have early ADR's at TS rest., best to enjoy the nighttime hours @ WDW!! But, that is just us - everyone is different!