the other thing that can limit the usefulness of a patch
is
if you are trying to patch road or trailside
in the rain
you will have a very hard time
so i carry one intact spare
either new or patched
and a patch kit
and if i have two flats
then i have to patch the second one

i suppose on a longer ride
in wet weather
after the first flat
it would be smart to patch the punctured tube
as soon as there is a few dry moments
or when shelter is available