In almost all cases you will need someone to help you move. No matter how strong you are, it is a bit awkward trying to get a bed up a few flights of stairs on your own. If you are moving out of home for the first time, say into an established place with friends, you will probably find that you won’t have that much to take with you.
Sure, you will have a whole bedroom full of things, but no kitchen, living room or dining room stuff. In this case you could probably get by with just asking a couple of people to help—your dad, brother, cousin or friend—and hiring or borrowing a ute or small truck.
On the other hand, if you have been living out of home for a while you have probably accumulated quite a bit of stuff. In this case it may just be easiest to use a removlist company. This means that you don’t have to organize friends to help you or hire a truck—the removalists provide the lot. I have heaps of friends who have moved into a place with two or three other people, and then had to move again for some reason.