These are the three main models of locks on the market. With a short search you could find variants, but the starting point is represented by these types. Unlike what one might imagine, a lock does not have an excessive cost: it is not difficult to find products even for a few tens of euros hdb door.
But the real cost, which considerably increases any budget, is that of installation and routine maintenance carried out by a professional. However, it is not difficult to mount such an item on your door yourself, the only problem may arise in the case of armored doors or magnetic locks.
For example, in the case of cylinder locks for armored doors, you first need to disassemble the door and then apply the lock (here are the best models ). For this reason, if you are not experienced in doing these jobs, it will be best to call a professional.
Instead, the only problem you might encounter with the magnetic lock is in size.
The most modern doors are designed to accommodate them without any problem, but it could happen that there is a gap of a few centimeters that compromises safety. Therefore, in our opinion, it is always better to spend a few extra euros and be safe for a long time, rather than having to change the entire door for a small mistake.
But a similar typology could not be exploited for the apartment, first of all for the higher costs, but also for the low level of security, since the code is easily replicable.