You should only use it if you want this design, but it depends. There's no specific answer. Also, for code optimization, leave that to JIT unless proven by a profiler that this code will in effect behaves better.

Do getters or setters come first?

For properties with both you're almost always going to use the setter before the getter so it's in a valid state.

Should you always have getters and setters?

Using getters and setters, is always, in my opinion good practice. One thing you should avoid is to have external entities mess with the internal structure of your class at will. Typical example, consider having a dateOfBirth parameter.