1998: 68k to PowerPC 2005: PowerPC to x86 (big to little endian) 2007: x86 to ARM (most of OS X ended up in iOS) 2013: ARMv7 to ARMv8 (whole new ISA)Despite all the moves, I always had the software I wanted. Emulators, universal binaries, worked and had close to zero visible effect on me.