How many of you are comfortable swinging a hammer and have confidence that you will hit where you intend? Can you drive a 16d nail in straight without banging the wood up with misses? A skilled framing carpenter can drive a nail to just below the surface with two hits – one tap to set the nail and then a power hit to drive it home. And they can do it all day.
I’m not saying you need to be that good, but unless you actually practice you will not be able to drive a nail when you need to. So rather than mess up a project you are working on you should spend some time driving nails, until you are at least competent at it. I recommend you get a hammer and practice with it until you become comfortable with it and then keep it.
My hammer of choice is a 20 oz straight claw Estwing. I have had this same hammer for over 25 years. As a homeowner, this hammer will serve you for the rest of your life. Get a smooth face head, do NOT get a hammer with a crosshatch pattern on its face. When, not if, you hit your thumb with the hammer you do not want the head to grip your thumbnail.
My recommendation is to buy a 30lb bucket of 16 penny nails, a hammer, and a couple of 2×4’s or 2×6’s. Then proceed to nail the two boards together. Don’t get carried away and do too many to start. For something you haven’t done before you can strain your arm if you do too much before you build up the muscles. Gradually build up the number of nails you drive each session until you build up the strength and coordination to nail two boards together – it is not as easy as it sounds.