I can't judge for this situation, though every time I looked into this, the fare difference between full-flex and the most restricted one was far more then all change/no-show fees requested on the most restricted fares. At least for J class........

And when rebooking, you will have to pay the fare difference anyway. So, better buy the most restricted fare and accept you every now and then have to pay the change/no-show fees. Much cheaper.

Or in Europe: Plan your Ryanair trip 6 months upfront for (often significantly less then) EUR 50 and just drop the ticket in case your trip gets cancelled. Much cheaper then purchasing a ticket 4 weeks (or even 1 week) upfront for 5 times that amount.