Landlord here in need of experts' help...

Is re-keying a lock the best way to "change locks" in between tenants? Should I just buy a re-keying kit?

How about buying the KwikSet SmartKey line of locks? (all I would need a new/different key to re-key the locks during each tenant turnover, correct?)?

In previous years, I would buy replacement KwikSet Tylo Combo sets but I just very recently realized that the key for the previous Tylo set would also work for the new set (so, apparently, over the last 5 to 7 years, I've never actually changed the key for the front door lock! Also, how is it that all the keys from different packs of a KwikSet model on the store shelves ALL work for each of the different lock sets?!?! I assumed each key in each pack was unique... I digress)...

I'm confident in my DIY skills but I need to consider that time is money. Please let me know how "lock changes" should be done in the most efficient and cheapest way possible.

I appreciate your input!