For me, it depends.... on my primary card that I use for almost all my
purchases and pay off every month, if I get an interest charge
(because of a cash advance or a late payment), I assign the interest
charge to a bucket. However, for loan accounts and credit cards I'm
paying off over time (and that I generally do not use to make new
purchases), I do not assign the interest to a bucket. These latter
accounts aren't part of my "cash flow." In other words, I did not
include the balances on these accounts in my starting cash flow and I
do not use the equity or credit in them to execute my spending plan.
For a credit card that is part of your cash flow/spending plan
(meaning you use it on a recurring basis to make purchases that you
account for in your spending plan), I think you could run into
problems if you do not assign the interest charge to a bucket. Over a
period of time (a long period it the interest amount is small, or
shorter if the interest amount is larger) if you didn't assign these
transactions to a bucket, you would think that you had more money than
you actually do.
Suppose you go through the year and you accumulate $500 worth of
interest charges on your credit card. If you don't assign these
interest charges to buckets, you reduce the cash you have available by
increasing the balance on your credit card without reducing the amount
of money in your buckets. This will create a $500 difference between
the cash you actually have on hand and the amount that your buckets
are telling you that you have. Given a long enough period of time, or
large enough interest charges, you could end up with a situation where
your cash available doesn't "cover" the amount in your buckets.
Grace to you,
Blair