Sometime ago I made a "stupido" decision to buy
all available 0603/0805 1% smd resistors from same series, just in case and having immediately access to these...
Yes, that's right, more than 1000+ values
and make things worse, some of the were not available in small qty (such as 500 or 1000 pcs), but only in reels.
Since then, never looked how much and so, mostly apply only smaller 040n/0201 limited values for new projects, until noticed that some 0805/0603 values are running out and consider to top-up these... Wow, at the time a cost was between 0.001 and 0.004 max, now at least 0.006 to 0.01nn
That's interesting (quick google search):
http://www.advancedmp.com/resistor-shortage-why-and-how/