I guess if you are storing in a wet and/or salty place you might need something extra. I've never needed it. One thing that I know for certain is that if you do need something extra to prevent rust, wax ain't it. Wax will not prevent rust on chrome. Like the rest of the guys are saying they are likely using WD-40 or the S-100 stuff.

 

+1 for the S-100, works great for polishing up the bike too! Take a little elbow grease to get off but protects the bike well