I hope this doesn't come across as a shill, but after having experienced Kwikset's SmartKey system, I'll never voluntarily buy another kind of lock or deadbolt: <a href="https://www.kwikset.com/smartkey-security" rel="nofollow">https://www.kwikset.com/smartkey-security</a><p>There's even an "onoz, I don't have the original key" tool for about $25 that allows one to buy locks off eBay or whatever without worrying about the seller including their original key: <a href="https://duckduckgo.com/?q=kwikset+smartkey+reset+cradle&t=ffab&ia=web" rel="nofollow">https://duckduckgo.com/?q=kwikset+smartkey+reset+cradle&t=ff...</a><p>I'm a fan