I have tons of non marine grade stuff on my boat. My iPod, my stereo, the cabin speakers, the "imitation" Ultrasuede interior fabric ($14.00 per yard as opposed to $70.00), every pot, pan, dish, spoon, knife and fork, our pepper grinder, our sheets, pillows, faucets, pats organizer bins, PB Blaster, throw rugs, Varathane oil based polyurethane for my cabin sole on and on etc. etc.
There are however things I do have that are marine grade. USCG rated fuel line, seacocks, AWAB hose clamps, UL tinned marine grade wire, plotter, radar, standing rigging, sheets and lines, Sunbrella, Strataglass, Starboard (plastic lumber), exterior varnish, VHF antenna and VHF, EPIRB, USCG flares, on and on etc. etc..
I buy from Wal*Mart when ever I can and do my part to support the Chinese instead of my fellow Americans who take joy in ripping us off every day at West Marine with 600% margins on some items!!
The bottom line is that living on the ocean I do see stuff wear out at my house only slightly less than on the boat if it's in the barn, shed or out doors. In the house with heating and cooling systems I see NO rust or corrosion on my electronic components and I eventually do on the boat...
80% + humidity on the inside of my boat during the summer and 50% or bellow inside my house during the summer months and they are 100 yards apart.. The difference is the humidity control afforded by my HVAC system..
This is what the ocean does at my house!! Perhaps i should have purchased a marine grade drill press?