I have owned one 2 "D" cell Maglite for almost twenty years in my stints in maintenance and HVAC-R and have never had a rust problem. The one thing I did not like about my Maglite is that no one has spare lenses for them. I had to replace the reflector once when I got silly and messed it up while cleaning it, and my local gun store had the reflector, but no lenses. I wrote Maglite to complain about them not pushing the stocking of lenses by their dealers, and they sent me 2 lenses free of charge with an apology. The one thing I do not like is the focusing feature of Maglites. I had a small double "AA" Pelican penlite that threw a very nice intense solid beam, but the cost of replacing the bulb assembly is too impractical for the type of abuse I used to put my tools through. I am waiting to see some of the new Pelican lights with the reflector facing bulb and what kind of beam they put out. Currently my 2 "D" cell sits in my bedroom with Radio Shack High Capacity Rechargeble batteries in it and a spare set sits in the drawer so that one set is always charged. I recharge them using a 25+ year old GE slow charger that requires 13 hours plug-in for a complete charge.
When I worked regularly, I used whatever the boss supplied, and when the power started to fade, I put in new batteries. The one flashlight I have that sits in my car with 6 "AA" batteries sits empty in the glove box until I need it and then I put the batteries in to use the flashlight. No battery leakage problems so far, and if I put a set of batteries in and they are dim or not working, I have two more sets. The double "AA" flashlight in my glove box is a $0.99 cheapie that throws a nice solid beam and works. I consider it a junker and it is almost 6 years old and still works great when needed.
Bountyhunter