I would say for most reels you can go at least 3 seasons without having to grease the gears. Oil is a different story. I oil my reels at least twice a year. Oil in bearings, grease on gears.
Hot sauce is some good stuff. they sell a combo pack with both grease and oil i believe. Just be careful with the oil, it has a red dye in it that will stain any fabric it comes into contact with.
oiling a spinning reel is as simple as it can get. Take your handle and end cap off (opposite side of handle). There is a bearing on each side. Two drops of hot sauce oil on each side. Put it back together and go fishing. If you see any old oil/crud in there you are past lubing and are needing a cleaning.
To clean the bearings you take the reel apart. One bearing will come with the side plate, the other is under the handle gear. You need to carefully remove the gear in the center where the handle connects to and that will reveal the other bearing. pop them out and flush them out. Safest way is to clean it all up with a paper towel and Q-tip the best you can and then oil it up and spin with your fingers, more crud will come out, keep wiping until its all gone and then re-assemble your reel. Two drops in each bearing and you are ready to fishing.
If you oil them a couple times a year and make sure no crud gets in there you won’t have to do a cleaning for at least 3-4 seasons.