I got a call from a friend the other day asking if I thought $800 was too much for his business to pay for a monthly phone bill.  Of course the answer could be yes, and it could be no.  It's depends on where you're coming from.  I have worked with companies where, if they'd have had an $800 phone bill they'd have celebrated by taking everyone to dinner.  I've also worked with companies where if they'd have had an $800 phone bill they'd have died of shock right on the spot.

Was $800 unreasonable for this company?  The answer is, it's all relative.  If you've been paying $300 a month, then yes, it's totally out of the acceptable range.  If you've been paying $1,200 congratulations.  You're doing great.  When we review financial statements (to look at our various costs to determine whether they seem normal) we never look at just one month.  Every expense needs to be taken in context.  It's impossible to tell what's “normal” or what's acceptable without that context.  That's why you keep monthly financials, even if you're a small company.  It gives you a chance to review 3 - 6 months worth of data at a time, where you'll be able to spot the anomalies immediately.

It's true that an income statement is just a snapshot of one moment in time.  But when that snapshot is taken at the same time every month (usually the last day) a series of those snapshots makes a movie.  Watching that movie carefully, month after month, will make it easy to spot negative trends, or other aberrations.  You are keeping financial statements, aren't you?  And you are reading them carefully each month, aren't you?  Because after all, it's all relatve.