Fishing reels are little machines which should give years of service with care and regular maintenance.
The biggest premature killer for reels is poor maintenance and salt/electrolysis corrosion. Salt conducts electricity and, with dissimilar metals being used in most reels, the residual salt eats poor-grade aluminium and magnesium found in many modern reels.
New Zealand’s salt water is in the higher range of salinity, so more maintenance is the price you pay for light weight reels with modern materials.
So what should you do with your reel after it gets wet? Lets start with the “don’t do” things… Petrochemical-based aerosols are not recommended, as they flush the oils from shafts and bearing and leave a fish repelling residue on the line. Some lanoline-based products expand rubber seals, destroy handles and build up in bearings.
Filling your reel with grease is also not a good idea as the salt sticks to the grease and eventually clogs up your bearings and gears with salty-gunky grease.
My recommended cleaning regime for fishing reels is a light detergent and fresh water spray. Do your drag up lightly while spraying, then dry the reel with a rag.
Preventative maintenance should be a drop of reel lubricant on spinning reel shafts and line rollers. Bait-cast reels have a port for regular oiling as do most overhead reels. Loosen the side plate screws and lightly oil them to ease disassembly for servicing at a later stage. Reels with level-winds have many driving cogs so need more maintenance to keep things moving (most are trouble, eventually). Leaving the drag wound up tight will see some components eventually stick together, so always back it off after use.
The odds of an early grave for your reel are reduced if you invest in mid- to high-end reels and keep them serviced and maintained. The side-of-the-road, dump-bin, sub $40 reels were born astride a salty grave, so good luck with them!