More compressor accessories! This is page two.
It is often worthwhile to get a whole package from a specific compressor vendor (compressor and dryer) as a single source for a system, and equally important in my view, a single source for warranty and maintenance as time goes on and things start to fail.
Consider that the compressor might have a 'V' belt drive, a variable speed drive, or be direct driven. Consider the up-front cost of each drive type as compared to the long term maintenance costs to keep that style of air compressor running.
There is a filter to clean the air entering the compressor intake.
There should be a filter at the receiver discharge line to the plant.
The oil used in the compression of air will need to be filtered, as will the air that is leaving the compressor pump and flowing into the air tank. That air needs the oil filtered out of it.
What types of filters comes with your compressor, how do you change the filters, what is the length of time between changes, where do you purchase replacement filter elements, and what is the skill level with changing each filter or filter element all have to be considered.
An hour meter is very useful for monitoring that run time, and having one is key to helping ensure that maintenance is carried out at the appropriate intervals.
How does the maintenance person check the lubrication levels on this compressor?
Ask the vendor what options you have for lubrication, what their recommendations are, and how stepping outside of their recommendation (perhaps you're convinced that another synthetic oil will work better for you) will affect your warranty.
Well you can't expect your compressor to last if it runs low on oil either.
Whether it's a simple sight glass, right up to a pressure and temperature oil sensor with alarm function, if your compressor contains oil, you'd best make sure you can check it easily.
Compressor oil is not good for downstream components including degrading rubber seals and polycarbonate air components.
Ask about percentage of oil carryover, how time affects the air / oil separation efficiency, and how best, with that type of air compressor, to keep compressor lubricating oil out of your air lines.
Carrying is OK for a small HP unit, as they might only weigh 40-50 pounds.
As your CFM needs increase, so does the horse power, and larger HP means more weight.
Consider a wheelbarrow type construction, certainly wheels of some sort would be useful, or even a fork insert area whereby you could lift the unit with a hand or powered fork truck.
If your air compressor needs to be moved, how will you do it?
Excessive vibration is a symptom of major failure in the system and you will want to know about it immediately if compressor vibration starts to occur. How will you?
If there are too many reasons why a particular compressor manufacturer's warranty would not be honored by them, well, it's like having no warranty at all, isn't it?