If I replace my main panel, will I need to fit AFCIs?
With the NEC straight up I think 210.12.D. Would require AFCI's where required (when the branch is modified, replaced or extended) the only exception is if the conductors are extended less than 6 feet with no new devices. Note I just checked with a inspector I worked with in my last county, he said 6' on either end with no new devices in our state would not require all the new code, I always read this as an extension to the end of line for a remodel with the total devices the same so even in my state and county there are some options.