If you know what you are doing then changing your locks is not so difficult. You can find lots of different styles of handles and different kinds of locking mechanisms for your door. Each kind of lock has its own properties so make sure you learn about them before you get new locks for your place. Read this piece for tips on how to change a lock and what kind of style you should choose.
You need to know what purpose your lock serves and what kind of security needs you have before you change it. Think about these styles before you buy a new lock.
If you want to change the handle on your closet doors and you will not need the locks then opt for a free through passage handle. You can find them in a knob style or in a lever style. You should make sure you don't have anything that needs to be locked up if you use this kind of handle.
IF you need privacy then opt for a privacy door knob. This kind of lock will allow you to unlock it from the inside by simply turning the knob or a switch. These are perfect for the bathroom.
If you need an entrance lock than you will want something that will help you to keep things secure in your garage or anywhere you might have dangerous things stored. You will want this if you need to keep sharp objects safe, tools, or machinery. You could put this on a fence that surrounds your swimming pool or your property if you want to keep trespassers out.
If you want to improve the look of your home than you can opt for decorative door knobs. These are often placed on French doors or you can put them on your pantry as well. These don't have locks so you will want to use them only in areas of your home that you don't need to make secure. These handles can be put on both sides of the door or you can put them only on the outside if you wish. On the other side will be a cap with a similar color and with fake trim if you don't have the knob on both sides.
Get a security single deadbolt lock if you want to secure your home from the front or back door. You can put them on interior door that connects to the garage and the inside of your home. You should use this lock if you have a door with no glass panes or else someone could enter by just breaking the glass and reaching into fool with your lock. You can also add a chain lock to your door to make it even more secure.
Try a decorative deadbolt and latch set which can be made either like a knob or handle and it can have a deadbolt lock and a door latch all together. Or you can use the two pieces alone as well. It all depends on what you need out of your lock.