  The transition from the asymptotic giant branch (AGB) to the final white
dwarf (WD) stage is arguably the least understood phase in the evolution of
single low- and intermediate-mass stars ($0.8 \lesssim M_{\rm
ZAMS}/M_\odot\lesssim 8...10$). Here we briefly review the progress in the last
50 years of the modeling of stars during the post-AGB phase. We show that
although the main features, like the extreme mass dependency of post-AGB
timescales were already present in the earliest post-AGB models, the
quantitative values of the computed post-AGB timescales changed every time new
physics was included in the modeling of post-AGB stars and their progenitors.
Then we discuss the predictions and uncertainties of the latest available
models regarding the evolutionary timescales of post-AGB stars.
