You want to keep a running
log of your business expenses, and you want to keep them separate from purchases that apply to your personal life.
Not exact matches
To meet this requirement, a taxpayer should maintain an account book or
log (or similar statement
of expense or trip sheet) that establishes each
business expense.
For travel, the IRS also requires you to keep a written or electronic
log, made near the time that you make the expenditure, recording the time, place, amount and
business purpose
of each
expense.
Having left it so long, and having no time to do the work yourselves, your best option is to find a good bookkeeper / accountant and provide them with as much detail as you can regarding the transactions
of the
business for all outstanding years, especially income deposits (your financial institution should be able to provide you with those records) and
expenses (check credit cards, lines
of credit, talk to suppliers for receipts, check your calendar to create auto distance
logs, etc..)
It's a good practice to hold onto, or scan into a company database, all
of your receipts for
business expenses; other
expenses, such as mileage, inherently need support by other documentation (e.g. travel
log).