Imagine you have an appendix chapter that contains a whole set of figures, but you don’t want them to show up in the list of figures.
The caption package does the trick for you:
\usepackage{caption}
and then use
\captionsetup[figure]{list=no}
to exclude figures from the LOF from that point onwards. Switching it on again can obviously be done using:
\captionsetup[figure]{list=yes}
Similarly, you can exclude/include tables using these commands:
\captionsetup[table]{list=no}
and
\captionsetup[table]{list=yes}