I have loads of rabbit hole areas. I just hope that my two are sensible enough to avoid them. Fortunately the old boy doesnt charge round but the youngster is a nightmare. We have in the past had someone to ferret the areas where they are but we currently dont have anyone. So we hope for a good dose of mixi to reduce the numbers.
Fortunately all our perimeter field fencing is high tensile electric fencing. It gets checked periodically in case any trees have dropped on it after high winds. Dont do a regular check but when I'm in an area of the field I'll generally have a glance at that section. Most of our internal fencing is either high tensile electric or stock netting with 2 high tensile electric strands on top. So very low maintainance.
I usually use a strand of poly wire to contain the boys in a section of the field or if I'm strip grazing. As I've been doing it many years I'm pretty experienced with knowing if you put up a slack temporary fence it will be down in no time so I have to say I make sure they are done properly, and it's very rare the animals get out. More of a problem when joyriders decide to have a jolly through the fields and dump cars.