When in doubt, pick a larger skip bin. It is more cost-effective to have unused capacity than having to re-hire a bigger bin; bins need to be picked up and delivered with special trucks which costs you time and money.
Road safety regulations are very strict on limiting skip bin filling up to the rim of the bin, so make sure you have one big enough to fit everything. If it goes over the rim, you will need to get a bigger one and move everything to it!
Asbestos, food waste, gas bottles, paints, oils, chemicals, empty chemical containers, and tree trunks are strictly NOT allowed in skip bins. They are hazardous waste for our diligent recyclers to pick through and for the environment. Such items should be disposed of via specialized waste collectors.
Make sure the skip bin is placed in the right place, with the right permits. If a bin is placed on council property (on the nature strip or on the road), you will need a council permit. We can handle that for you. Costs vary by council.