durative
long-pending
imperishable
long-termly
abiding
durable
perdurable
enduring
undestroyable
indestructible
long
macrobiotic
protracted
longeval
extended
perpetual
secular
long-span
evergoing
long-lasting
old-line
make old bones
longue durée
until the cows come home
inveterately
hot minute
until the cows freeze over
lifetime
eon
ongoing
at length
with ages
chronic
permanent
continuing
decadeslong
donkey's years
longwhiles
old
donkey's ears
lengthen
eternity
longevously
long haul
for the long haul
longstandingness
plurennial
longirostrate
outkeep
age