Oh that's weird, I'm right now as I type this, listening to a CDDA disc I burned in 2009 and it's flawless. At least nothing's getting through the error correction; I suppose I could scan it and check the C1/C2 error rates, but I don't know what they were immediately post-burn to compare to. (I used to scribble the burn date on the front, so combined with the ATIP batch data, I could eventually build up empirical data about which ones failed prematurely. Never came up with enough failures to produce a signal from the noise, but I have all these discs with burn dates on them.)
DVDs were pretty much the opposite. I burned a lot of DVD coasters. Had even more that failed a few months into service. Dual-layer were so expensive for the good blanks, and so dismally unreliable for the cheap blanks, that I seldom bothered -- two mid-grade single-layer discs were cheaper and more reliable.
Floppies have been hit-or-miss for me, they're more susceptible to mildew if stored in a damp basement, and cleaning solutions are a you-get-one-shot affair since you have to cut open the jacket and remove the flexible media. But if kept dry, I've had decent (95%?) success rates from mid-80s-to-early-90s floppies. A drive cleaning disc is essential.