I had a new angle on this idea today. Apologies if it's been discussed before - I searched and couldn't find anything.
I recently spent 3 hours on the phone with my cable company (they don't talk to each other, long story) to save $10/month on my internet package. Assuming this discount lasts forever, I'd need an extra $3k in my stache at 4%SWR to cover it. Obviously this particular discount is temporary, but the concept applies to any kind of indefinitely recurring expense.
$3k in my stache is nearly a month of work at my current savings rate. That means I just spent 3 hours of time to save a month, which is a 5200% return on my investment over the time horizon of my career.
The next logical step is to note that if my time is worth say $30/hour, then spending an hour ($30) is financially beneficial if it can save me $0.10/month indefinitely.
That seems totally absurd but the numbers work out. Did I miss something obvious, or are recurring expenses actually that bad? Is it really worth investing an hour to figure out how to save $0.02 every time I buy a jug of milk?