If you have to move and don't have much stuff, you are likely thinking that you could take care of the move yourself. If all you have is a couple of carloads of clothes and books, that could make sense. But if you have a fairly normal amount of belongings -- kitchen goods, linens, and maybe some small furniture -- it's going to take more than a couple of trips in a car. Renting a van or truck on your own sounds like a solution, but you may want to pass on that and have a local moving company move everything in one go. Doing so would protect your health, your belongings, and your moving budget.
Cost
Hiring a moving company is, at first, the more expensive-seeming of the two options. However, it's a fixed cost that doesn't change unless the move takes a very long time because local movers tend to charge per hour.
If you rent a van or truck, the initial rental costs will seem very low, but the total amount you pay can change drastically because of the mileage you rack up. Many truck and van rental places don't include mileage for vehicles used for moving, which means your final cost can spiral upward, especially if you have to make multiple trips. If you're concerned about sticking to a budget, having a moving company handle the move is best.
Injury Risk
Even light boxes can tweak your back and strain your shoulders. If you do the moving yourself, you're at risk of injury. If movers handle the move, they are the ones risking a problem, though they are insured because of that risk. This is a straightforward factor; if you prefer not to risk injury, have someone else handle the move.
Driver Safety
Vans and pickup trucks, and even small box trucks, are designed to be drivable by just about anyone, but they can still be awkward if you've never driven one yourself. That leads to an increased risk of having an accident and getting injured or damaging the truck. Want to avoid that risk? Hire a moving company.
Efficient Space
Movers are going to be much better at stacking everything so that it doesn't fall over during the move (thus reducing the risk of damage). Unless you're used to packing van and truck beds with boxes and furniture, you likely aren't going to be the best at securing everything. Again, hiring movers will take care of that problem.
It may seem like a chore to call and get quotes, but it's actually very easy and takes only a few minutes to find out what the move would cost. Start contacting moving companies now to find the best combination of service and price.