The first warm Saturday is when everybody pulls the cover off and wants to go. Twenty minutes of checking first will save you a breakdown later.
First, if Jared winterized it: check the tow switch
Every electric cart he services goes into TOW mode for the winter. A cart in tow mode will not drive, and that catches people out every single spring.
Flip the switch back to RUN before you do anything else. It is usually under the seat. If the cart seems completely dead and you know it was serviced over the winter, check this before you check anything else, because nine times out of ten that is all it is.
Both gas and electric
Tires. Pressure drops over a cold winter. Air to spec and look for flat spots or cracked sidewalls from sitting.
Brakes. Check the pads or shoes and adjust. Brakes that sat all winter often need adjusting even when nothing wore out. Test them properly at low speed before you trust them on a hill.
Grease every zerk. Quick, cheap, and skipping it is how front ends wear out early.
Look for mouse damage. Under the seat, in the wiring, in the air box on a gas cart. Check before you turn the key, not after.
Check the frame. Especially on an older steel framed cart. Look where the battery rack sits and where water pools.
Lights and horn. If you have them, confirm they work now rather than at dusk.
Electric specifically
Water the batteries. Top off with distilled water to the proper level. If the plates were exposed at any point over the winter, some capacity has already been lost.
Clean the terminals. Baking soda and water for corrosion, then a protectant.
Full charge and a load test. Charge it completely, then actually drive it for fifteen or twenty minutes, ideally including a hill. A pack that sags badly under load is telling you something a short flat test around the driveway will hide.
Check the charger. Confirm it is completing its cycle and shutting off properly.
Gas specifically
Fresh fuel. If it sat with untreated fuel, drain it and start fresh rather than hoping.
Oil. Change it now. This is the right time for it rather than going into storage, because the cart then runs the whole season on fresh oil.
Air filter and spark plug. Clean or replace as needed.
Expect some cranking. It has to pull fuel through. If it fires then dies repeatedly, the carburetor probably needs cleaning.
Summerize while you are at it
Heat does more damage to a battery pack than cold does. Two habits worth starting now:
Park in the shade wherever possible. A cart baking in the sun all afternoon ages its pack faster than one that does not.
Check water every couple of weeks in July and August, not monthly. Heat drives water loss and the schedule that worked in May is not enough in August.
Or just book it
A spring service covers all of the above and costs a fraction of a mid season breakdown. Jared runs these across the valley from March. Call 406.270.9346 and get on the schedule before everybody else does.