Brad,
First of all, do you wash all your bowls every week? If so, your math is correct. If not, then you have to factor in the $10 over the time period you use for one complete washing cycle. So if you clean/replace each bowl every two weeks, suddenly your price is down to $20 a month.
When you just look at the outlay of money, I used to feel the same way. But then I did the math.
Figure out what an hour of your working time is worth. For example, you are washing 125 bowls at a session (based on your $10 number). How long does the actual washing take? An hour, two hours? If you are fairly quick, you might average 2 a minute (including time to fill the sink/bucket, wash, dry and drain dirty water) and get the whole stack done in one hour. So at that rate, you are working for 1 hour to save $10.
Now, if someone else offered you $10/hour to come wash their snake waterbowls, would you do it? If so, great. You have made the right decision.
If not, why not? Not enough money? That's what you're paying yourself.
Even if that was time you would have spent goofing off, you are still working for an hour doing rather tedious work for $10. If you are slower and it takes more than an hour, you are paying yourself even less.
Just another way to look at it. At least, that's how I justify the expense for myself, but I'm only in for $2.40 a week.
Chris
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Chris Harrison
San Antonio, Texas