Although, of course, the feasibility of giving your fuzzies 24-hours Havoc
Time really has to be an apartment-by-apartment/ferret-by-ferret decision,
for my part I can say I haven't had any problems with letting my three out
all the time.  My apartment is a large-ish efficiency (poor college
student :) with an easily ferret proofed kitchen: the stove is too low to
crawl under and with stratigic use of thin cardboard and
that-gummy-stuff-for-hanging-posters I blocked the refrigerator openings.
 
Other than that I have always found that my guys always tend to
dig/poop/knock things over in the same places.  So, basically, when they
decided they liked to scratch under the closet, I put a carpet runner there.
When one started to use under my table as a litterbox, I sewed them some
sleepy-sacks, put them there, and now it is a place to hide toys, instead.
All in all, I have never encountered any problems that couldn't be fixed by
a few dollars.  [Of course, if you are REALLY ambitious you could try to
train your ferrets not to do naughty things, but it probably isn't worth the
effort ;)]
 
On the other hand, however, since I got my first ferret (~2 yrs.  ago)
depending on where we were living, etc.  their run-time has varied from
full-run to as little as a few hours.  Other than obviously being less hyper
when they come out, I can't really say I've seen incredible temperment
differences depending on out-time.  (Although being less hyper helps them be
less nippy :) If you can give them the run-time, go for it.  If you think
you may be endangering them, they surely can get by on less.
 
                -Val, with Gromit, Gimpy, and Noah
                 Madison, WI
[Posted in FML issue 1836]