Because everyone loses keys at some time, you should always keep a spare key for each lock you use. When you don't have one to replicate, it's always easier and less expensive to have a duplicate manufactured than to have one "originated."
Depending on the type of lock, Gkeez may be able to produce a "key by code" very cheaply if you've misplaced your last key. On the face of many utility-type locks, a key code will be stamped. The locksmith knows which key blank to use and how to cut it by looking up the code. Code BT01, for example, is for Tuff Shed lock; it informs the locksmith that the correct key blank and it defines the type of lock.
Making a key by code is more expensive than just copying a key since it takes longer and necessitates the use of sophisticated machines and reference materials. It normally costs between $10 and $20. Price is most often determined by whether the key is one-sided, two-sided or a tubular type. Of course, there are exceptions.
Locks for which codes are typically visible include those for office furniture, car luggage racks, tool chests, towel dispensers, cabinets, file cabinets, gum ball machines, old steamer chests and low end key-locking safes.
Before you do anything rash if you lose your last key, check for a key code. (A magnifying glass may be required.) It's likely that Gkeez can create one for you. But make two of them!