^^^ this. I've had my tank set up for about a week and (especially with an aquarium/glass enclosure) it's really helpful to be able to monitor day and night temps, humidity and fluctuations. I've had to make several adaptations to make it work.... Much easier pre-BP.
And another word of advice- don't always trust the pet store people. I've been laughed out of Petsmart twice when they found out I "wasted" money on a thermostat.