There is a great deal of freedom to propose changes from the standard
cosmology history of the universe prior to Big Bang Nucleosynthesis.
In this talk I will highlight that tweaks to standard cosmology can
significantly boost or deplete the expected relic abundance of dark
matter. I will highlight some classic applications of these ideas in
the context of neutralino dark matter, discuss recent work applying
these ideas to different dark matter scenarios, and outline some new
ideas related to cosmologies with non-standard equations of state.