i've researched quite a bit on locks
I assume you're talking about replacing the deadbolt
I have this schlage lock myself
Schlage Lock Company BE468CAM716
Why did i choose the schlage? well first, almost every and all smart lock/locks are junk. The "hardware" the "lock" itself is junkish, and of the smart lock brands, "at least" schlage is higher quality deadbolt.
There are horrible smartlocks like from kwikset(very common) that cost hundreds, but you could easily defeat the lock with a screwdriver and strength (stick it in the slot and twist like hulk), it'll break b/c the insides are made out of plastic.
So out of all the smart locks out there, at least schlage has good internal hardware. (but lets be real, the deadbolt itself is no different than a $30 schlage deadbolt i have opened them up and rekey'd em)
Mine is the top end one, b/c i wanted autolock, as in you unlock it and close your door, and 30s later it will auto lock, also it includes zwave tech to integrate into your home automation (unlock from app too)
if you don't care about those 2 features at all, you can save a hundred bucks and go for this model down
Schlage Touch Camelot Deadbolt (Aged Bronze) BE375 CAM 716
again, yale/kwickset smart locks, AVOID (these are the common ones you'll see in big box stores too)
while youre there pick up a box of 3in construction screws
Grip-Rite #10 x 3 in. Philips Bugle-Head Coarse Thread Sharp Point Polymer Coated Exterior Screw-PTN3S1 - The Home Depot
like 50screws for 10bucks, replace all the screws in your door jamb, deadbolt strike plate this way it'll bite into the stud. (if you get the schlage they come w/ 3in screws) but you should also replace the screws at the hinges.