I liked this idea from Get Rich Slowly:

The 30-day rule is a simple method to control impulse spending. Here’s how it works:

1. Whenever you feel the urge to splurge — whether it’s for new shoes, a new videogame, or a new car — force yourself to stop. If you’re already holding the item, put it back. Leave the store.
2. When you get home, take a piece of paper and write down the name of the item, the store where you found it, and the price. Also write down the date.
3. Now post this note someplace obvious: a calendar, the fridge, a bulletin board. (I use a text file on my computer.)
4. For the next thirty days, think whether you really want the item, but do not buy it.
5. If, at the end of a month, the urge is still there, then consider purchasing it. (But do not use credit to do so.)

I can think of so many places this would work.  First, for those firm technology and gadget purchases or upgrades, sit on the impulse for a month.  If you still think you need it, make the purchase.

Second, if you have an irrational client demand you do something that you don’t think is particularly prudent (like filing that motion to compel to get the lawnmower back from their neighbor in the middle of winter), suggest that you wait 30 days, and if they feel it is still important then, you’ll do it.