How much insurance can you afford?

Most chips designed have debug logic. Debug techniques including visibility of a debug bus, controls for complicated circuitry like RAM self timing or high speed I/O, and clock control have been used for many years by many companies. Many older techniques like scan enabled debug and on-chip logic analyzers and emerging techniques like specialized on-chip instrumentation look interesting but are not used in most designs today. The big question is why don't some of these techniques catch on more and how much debug logic is needed to mitigate the risk of slow time to market?".