If a permanent has multiple instances of cumulative upkeep, each triggers separately. However, the age counters are not connected to any particular ability; each cumulative upkeep ability will count the total number of age counters on the permanent at the time that ability resolves.
July 13, 2013 · Magic 2014
If a creature has multiple instances of flanking, each triggers separately.
September 30, 2011 · Innistrad
If a permanent phases out, its status changes to "phased out." Except for rules and effects that specifically mention phased-out permanents, a phased-out permanent is treated as though it does not exist. It can't affect or be affected by anything else in the game.
June 17, 2011 · Commander 2011
If a permanent phases out, its status changes to “phased out.” Except for rules and effects