Well, it's not so much laser light as it is the light from bulbs or the sun. True, the laser will have affects in time, in theory, but I would think all other factors would affect it first, including the other light sources.
Because of stocking issues, wild price variations, and potential for "bait and switch" (sending the so-called "same item" even though the model is not 100% the same), I no longer regularly suggest
Buy.com in the USA or Canada. Right now, we know
Amazon has the good AZO DVD-R for $35 CAD/CND per spindle, which is a decent price.
How much are the 50 packs from
Buy.com? Usually two 50 packs costs more than one 100-pack, from either store. Be VERY SURE that those are not Value Series or Life Series discs, either.