Locks are integral for protecting the home from external entities. The most important times to rethink locks are when you purchase a new home, when you lost a key or the effectiveness of the lock. Rekeying means changing parts within the lock itself, mainly the lock cylinder. The lock housing would remain the same but the old key would not work. Replacing is removing the entire lock housing for a new housing and obviously, new keys. Both rekeying and replacing locks may require a locksmith unless you are familiar with locks. Opting for one over the other is discussed below.
Rekeying a lock is essentially cheaper than replacing it. To replace a lock, you would have to purchase an entirely new housing, ensuring that it fits the area where the old lock was. When replacing locks, you may want to splurge on a better brand or a more secured locking mechanism. You would then have to pay a locksmith to replace the lock itself because you would not want to compromise the security of your home by replacing the lock yourself. If you are rekeying, the only components that would be changed would be the key pins and the new keys. Key pins are less expensive than an entirely new lock and the locksmith can easily supply and change this without you having to go search for it.
Rekeying would also mean that there is some limitation to upgrading the security of the lock itself whereas with replacing, you can purchase a new lock to upgrade your existing security features.If your home was recently broken into, then obviously the old lock was subpar as it could not keep out the thieves. Rekeying this lock would mean that you are putting back the same subpar lock and therefore the security of the lock itself was not upgraded. Replacing the lock would ensure that the lock can be upgraded and customized to suit your needs.
Customization is important for enhancing security features. For instance, if the old lock had one dead bolt, you can replace the lock with one that has two dead bolts or more. You would not only have a new set of keys, but you would have more peace of mind with extra security. When purchasing a new home, it is good practice to change the locks so that the previous owners would not have access to it. While rekeying would satisfy the initial purpose of changing the locks, replacing can offer an upgrade to the brand.
Rekeying or replacing depends on your needs and your pocket. If you are happy with the current lock then rekeying is the better option. However, if you are dissatisfied and need an upgrade, purchasing would be the better option. In the end, it all depends on your pocket. I would always choose the most affordable option if money was an issue but if money is not an issue, then splurge on a new lock with more security mechanisms. It would not make any sense to purchase a new lock with the same security features, you might as well just rekey the existing lock.