I was curious after seeing the CUSA map on TV, so I started looking at longevity in the G5. 34 of the 135 FBS schools will have switched conference affiliation between 2022 and 2025. Only 24 G5 members were in their current conference in 2010 and 12 of those are MAC members.

CUSA (1 member prior to the 2011 realignment)
Oldest UTEP 2005
Nobody else prior to 2013. FIU, MTSU and La Tech entered that year.
Newest-Kennesaw State 2024, Delaware 2025

Sun Belt (4 members prior to 2011 realignment)
Oldest Arkansas St., ULL 1991
Only others prior to 2013 were Troy 2005, ULM 2006 and USA 2012 (although they have been basketball members since 1976).
Newest-JMU, ODU, Marshall, USM 2022

AAC (started 2013, but if you count BE, 1 member prior to 2011 realignment)
Oldest USF, Memphis, Temple 2013 (USF was in the preceding BE in 2005 and Temple in 2012)
Newest-Army 2024

MWC (6 charter members, only members prior to 2011 realignment)
Oldest-Air Force, Wyoming, CSU, UNM, UNLV, SDSU 1999
Newest-SJSU, USU 2013

MAC (all 12 prior to 2011 realignment)
Oldest-Ohio 1946, Miami & WMU 1947, Toledo 1950, Kent. 1951, Bowling Green 1952
Newest Buffalo 1998
10 of 12 were members in the 70s, although NIU left and came back in 1997.

Quickly for the P5
Pac 2 of 2 before 2011, both rejoined in the 60s.
Big 10 11 of 18 before 2011 with 9 going back to the early part of the 20th century
SEC 12 of 16 before 2011 with 10 of those 1933 charter members
Big 12 6 of 16 before 2011, all 6 1996 charter members
ACC 11 of 17 before 2011 with 3 of those from the 00s, 1 from the 90s, 1 from the 70s and 6 charter members from 1953