Monday, August 27, 2007

How Much do You Pay Your Machines?

Greetings, Robot Lords.

The Pitch

How much do you value your free time? In Stephen King's The Stand, the Walkin' Dude comes by Mother Abigail's place in the guise of a vacuum cleaner salesman, making the pitch that he's not actually selling her labor-saving vacuum cleaners. Instead, he's selling her cool lemonade sipped in the shade on a hot day, time to lazily read a novel, or time to do essentially whatever Mother Abigail likes best. The premise is simple and appealing: we buy (or make) machines which save us drudgery, and then allegedly have more free time.

The Catch

In reality, our time-savers often end up owning us instead. It takes a lot of time, energy and money to maintain every piece of equipment we buy. On the other hand, I have a lot more free time than any subsistence farmer I've heard about, so there must be a good side to this tech too. How do we know if a given piece of labor-saving tech is worthwhile?

The Players' Salaries

One interesting analysis is to figure out what effective wage you're paying your labor saving device for your extra free time. Everything doesn't always boil down to money: it's not as if chores are equally onerous (I enjoy gardening more than cleaning the bathroom), but quantifying the hourly rate of free-time-saving makes for an interesting analysis nonetheless. Here's a summary table, then I'm going to talk a little more about some entries. Here "machine wage" isn't how much you pay per hour of operation - it's how much you pay per every hour of labor it saves you. I've ordered this list in descending order of utility.

ItemPriceCost/yLifetime (y)Hours saved/weekHours savedTotal CostMachine Wage

Dishwasher 500
5 3 780 500 0.64
Non-stick fry pan 100
20 0.05 52 100 1.92
Lawnmower (electric)
4001 10 0.25 130 410 3.15
Newer computer 1500
2 1 104 1500 14.42
Kitchen Mixer200 1 20 0.0096 10 220 22
Melon baller 10
10 0.00064 0.33 10 30
Car 5000 2000 5 1 260 15000 57.69

  • I'm a dishwasher evangelist. I've been responsible for (or at least influential in) the decisions of no fewer than 5 households I know to acquire a dishwasher by hook or by crook. (If you're renting, look into portable dishwashers - that's what I own.) Until today I just always had a hunch that dishwashers were good time-savers, but the hard numbers really nail it for me. Operating a dishwasher (in hot water and dish soap) costs about the same as washing by hand, and by my analysis my $500 dishwasher will save me 780 hours of scrubbing. Since I value my free time more than 64¢/hour, owning a dishwasher is a no-brainer.
  • I just bought a $100 super-high-quality frying pan, with (I kid you not) embedded diamonds as the non-stick coating. So far I have no complaints performance-wise: I get an even heat and the food has been scrumptious every time. As a side effect, I estimate that I spend about 3 minutes per week less cleaning, since now I can use this pan instead of my older stainless steel pan (which was a pain to scrub). Those 3 minutes per week over the 20 years the pan should last amount to 52 total hours saved, so I'm "paying" this machine $1.92/hour for the privilege of not washing dishes.
  • If I were to buy a new computer (something I dream about way too often) I might spend about 1 hour less per week waiting for my numbers to crunch (I'm a "power user": I run intensive numerical operations on a regular basis; for word-processing I doubt a newer computer would save more than a minute or two per week). If the new computer I'd keep for about 2 years, then it would save me about 104 total hours, so upgrading now (for $1500) would be like paying the machine $14.42 for every hour I save not waiting for that progress bar to end.
  • I broke down and bought one of those designer kitchen mix machines the other year. We barely use it, truth be told. If it were to save 15 minutes twice a year, this $200 machine would save us 10 hours of work over its 20-year lifetime. (Inside, I doubt it will save that much time, but the truth hurts sometimes.) It really sucks power too, so I guess its lifetime cost (price + power) will be $220; meaning we're paying it $22 per hour that it saves us. (Note: this mixer brings an invaluable quantity of ancillary joy to my better half merely by gracing our kitchen - which is precisely why this kind of analysis didn't have the last word.)
  • We also own a melon baller! If it saves us 2 minutes a year (we hardly use it), we're paying it $30/hour for the privilege. Maybe single-purpose kitchen gadgets should be contraband.
  • Last (but not least) we don't own a car. I can get to and from work without one (and, considering the parking around where I work, biking is faster), even though it makes doing errands a little more tricky. I estimate I spend about 1 hour more per week doing errands because I can't just hop into a rust bucket. (Aside: if I were to offset time I don't have to spend in the gym because I bike, this 1-hour figure could very well be negative!) In any case, were I to buy a car, over 5 years it could well cost $15,000 in insurance, depreciation, maintenance, parking and fuel. For each of the 260 hours it would save me, I'd be paying it $57.69: a pretty lousy deal. I guess I won't be buying a car until my lifestyle requires one.
The Last Inning

On that note, let me hand it over to you. The numbers I've presented are highly personalized and might not apply to you. I do a lot of serious computing, and even for me a new computer only barely makes sense. I live close to work, so biking is a great option. We do a lot of entertaining, and thus a dishwasher is pretty much essential. If you truly need a car, or if you don't entertain or run scientific computing experiments your personal table is likely to be quite different. Still, I encourage you to do the same sorts of analyses before listenening to the Walkin' Dude.

Rule your 'bots with an iron fist!


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