Yes, 5 years. Granted that's for uncoated steel line, such as used on the 2000-2007 Chevy Silverado and others. We keep GM brake line kits in stock for those (complete vehicle kits are only $80-$90 right from GM). The replacement GM line ARE coated steel so maybe they learned their lesson, lol.
Not that long ago I replaced the rear brake lines on a 2010 Buick LaCrosse. It's the massive amounts of road salt used in the winter months that does them in.
Already have seen vehicles as new as 2012 with rust pinholes over the rear wheel openings. My "bosses" 2011 F150 has the cab corners rusted out already. Only state where you replace exhaust manifolds because they ROTTED OUT, or even cylinder heads with holes rusted in them and either leaking exhaust or coolant. Ever see a brake caliper leak fluid through a rust hole in the caliper housing? I have and it's not pretty. They rot from the outside in, not the inside out btw. Yes, it does really suck......................................Fortunately Carquest is right next door so when we need yet another cylinder of acetylene or oxygen for the smoke wrench it doesn't take long. We go through a lot of it, especially when you end up having to heat half the fasteners to get something apart. All a part of the job when you live in a rust belt state.