For two reasons, it is good to keep track of income and expenses
related to modeling assignments.

A) To make sure that records are straight for tax purposes.

B) To make sure that your modeling assignments produce more
for you than they cost.  Income is simply what you get paid
per session (including transportation money, if that is part
of the agreement) .  Expenses should include phone bills,
transportation expenses, expenses for advertising and publicity
publicity (printing business cards and resumes, mailing
letters and resumes, putting together your portfolio, agency
fees and association memberships ) .  A second type of expense
which can’t be measured in a “reportable” way is expense of
time. Time spent in keeping a short appointment at a place
some distance away might be better spent keeping a longer
appointment closer to home, unless the more distant
appointment offers greater rewards in ways that are not
financial. See Appendix C for a financial records form.