It's confusing me, I would like for sims not to get sleepy as fast. Seems every time I go out on the town the simmies are all tired. Should I use delta or decay, and should I raise or lower? Thanks in advance!

Motive Deltas are what speed up or slow down motive replenishment while a sim is doing something that already replenishes that motive. So, in the case of energy, the Delta will speed up or slow down the increase in energy sims get while they are sleeping.

Motive Decays are what speed up or slow down motive decreases. So, in the case of energy, the Decay will speed up or slow down the energy a sim uses throughout the day but also especially while doing things that exert more than average physical activity (like jogging, exercising, woohooing).

Sounds to me like you want to adjust the Motive Decay for energy to something lower than 1. Perhaps try 0.65 and see how that goes for a couple of sim days. If you find that sims who are actually being simulated are not tired enough to go to bed when it would be time for them to do so or they keep waking up at 3 am all refreshed already, then perhaps a gentler adjustment like 0.8 would be in order.

Thank you, that clears up a lot! I'll try .8 first just to be safe and adjust it from there. Appreciate it.