Every knife I've bought new has needed no break-in period and have performed admirably from day one, except for the Cold Steel knives. The Code 4 and Lonestar Hunter I got new had some of the hardest-to-open locks I've ever witnessed, even harder than the Manix BB lock, and the lightly used Recon 1 and Voyager that I received as gifts were just as bad even when I got them after someone else had them 'broken in' for me.
Cold Steel is 0 for 4 for me in making easy-to-use knives, while Benchmade, Spyderco, Kershaw, and even SOG have sold me knives that are not only easy to open but also easy to close. The only common trait in knives that are hard to operate is the Tri-Ad lock, which is so excessively overbuilt that it makes operation difficult, something that I am not willing to sacrifice for an overbuilt folding knife that survives tests I will never do to my knives.