A clothes dryer install is often more than the machine. The venting, the hookups, and the room decide much of the scope, so read the quote for those lines before you compare totals. The unit's own service life is covered on its clothes dryer page.
The duct run
Length and turns in the exhaust duct add resistance and set how much work the install takes. Ask how many bends are in the run and whether the installer plans to shorten or reroute it. Ask what duct material is planned. Flexible plastic or foil is often not permitted by the appliance instructions, and it may need replacing. Ask whether the exterior vent cap needs to be replaced or added.
The hookup
An electric dryer needs its own supply circuit at the correct voltage, and the outlet has to match the plug. A gas dryer needs a gas line stub within reach and a shutoff valve. Ask who runs the new supply or line, and whether that work is in the quote or a separate job for a licensed electrician or plumber.
The room
Look at where the dryer sits, how much clearance it has behind it, and how the old unit will be removed. Tight laundry closets add time. Stairs, a narrow door, or a cabinet in the way add labor. Ask the installer what happens if the room needs changes.
Read the quote line by line
Ask the installer to list each item: removal of the old unit, the new unit, venting parts, the hookup, hauling, and any permit or inspection. Items missing from the quote are the ones that tend to show up later. Ask for them to be written in before you agree.