You set it once and forget about it.
7 day programmable allows you to customize M-F and Sat&Sun separately. For example, I keep the A/C down for the entire weekend, where during the week I have mine set to go up a little bit during the day.
The Honeywell 7 Day is a great thermostat, it will always hold your settings, its powered by your system and has a back up battery for when power to your home is interrupted. Thermostat will tell you if back up battery ever gets low which lasts a few years, I would avoid other brands, me personally.
We actually have two HONEYWELL 5+2 DAY THERMOSTATS which came with our home and now 12 years old. The 5+2 lets you set weekday schedule and weekend schedule.
The 7 day is a step up as you can program each day.
I would avoid wifi thermostats (such as nest ect) too, you will save more money with the Honeywell 7 Day.
The only time a wifi might be good is for a vacation home, or home you do not live in. Other then that and ANY WiFi thermostats, its nothing but marketing selling you a gadget with "sizzle" and does nothing and I mean nothing to save you more money then the non wifi thermostats. They are HIGH marketup profit generating gadgets.
With that said, for the gadget lover, that is great! Its a great device.
For the person looking to heat and cool their home efficiently and care free as possible, Honeywell 7 Day.