When thinking about the film making equipment you will need for your project, you will need to make a list as soon as your budget and schedule have been worked out. This is when you will need to contact film making equipment rental houses to see which ones have the best price on what you need. Some of this equipment is used often and you may need to reserve it much earlier than you will actually need it.
You will need to get a list of vendors that offer the film making equipment rentals that you need. Some rental houses can put together a complete package for you, and others may be a bit more constrained. As long as you have a complete list of equipment needed you will be able to find the right rental house to serve you.
When you contact the vendor, ask if they will have the equipment you are going to need by the time you will need it. Tell them what your project will require in the line of film making equipment. Most of the rental houses are current on the latest equipment, and could help you with information you weren't aware of.
It is imperative that you reserve the equipment for the dates of your shoot. This should be done in advance, and is called a hold. This does not mean you will need to pay for the equipment before you pick it up. If the film making equipment has already been put on hold for someone else, you may need to accept a hold for a later date. If you know that the date you have given is the date you will be getting the equipment, ask the vendor if you can firm your order. The rental house will contact the people with the hold prior to you and ask them to firm the order or give up the hold. When you firm an order, you will be obligated to pay for the equipment from the day you have the hold, even if you don't use it then. If your plans change, you will need to contact the vendor as soon as possible so they can make other arrangements with other customers.
Since you are renting equipment that has had several users, it is a good idea to test it out before you are actually ready to shoot the film. The vendor is not liable for anything if you use faulty equipment and waste time and money. Most rental houses will ask you to show proof on insurance, if anything should happen to equipment while you are using it, you are responsible for replacement. If you do not have insurance, the rental company will put you in touch with an insurance company that will cover the production.
Make sure you get a signed agreement on the terms of the film making equipment rental, cost, time of pick up and return, and a list of liability and responsibility terms. Check the equipment when you pick it up to make sure it is all there. It is much better to find a missing element while at the rental house than when you are ready to shoot. Check everything with your list to make sure nothing has been left out, you will avoid wasting time on trips back to the rental house to retrieve missing equipment. Check everything over thoroughly and don't miss anything, no matter how small. You may want to pick up the equipment a day or two before the day you will be shooting. This will give you plenty of time to test the equipment so there will be no surprises.