The aim is to save time.
Slumpbuster has the attitude (correct, in my opinion) that a few seconds saved on each part of each job may well allow you to do an extra job a day. If an electric reel saves you 20 seconds a job then over 15 jobs you have five minutes. Find another couple of ways to save 20 seconds and you'll have saved 15 minutes, so you'll be adding another job. I found about half a minute a job just by dropping off my "windows done" envelope as I did the job rather than going back to the van for it every time.
I was told on here that I clearly live to work once for expressing sentiments like these, but if something involves no effort, just doing things a little more efficiently, why would you NOT want to do it?
For those of you who don't want to make any more money, you could even spend the 15 minutes at home with your feet up.
Vin
I honestly can't see how mecanically sorry bout the spelling, winding the hose reel up is better than winding it up by hand,just seems like another diy gadget,am not trying to offend at all.better kit being a diy thing that reels hose in for me?
I can't honestly belive that if there is an easier/quicker way of doing something, why on earth that you wouldn't do it, as long as the financial impact was to great!! 
I can run 2 miles pretty quick, but belive me I would rather drive my car than run every where! 
Yes, but not just time. I get tired, especially at the end of the day.My arm used to ache, and my bicep would throb at night.
There are other ways to do this.Two vans for instance can probably achieve more work and i still have to half kill myself every day to hit a figure.There is no right and wrong way, but i love the idea that a machine does the work.
The thing about the slips is good thinking.I'll have to think how i can use vin's idea.One thing i have done is bought a date stamp for slips.This is because price, date ,and house number often get transmogrified in my head and i write the wrong info.I also have a stamp for envelopes but i do this en masse, and a stamp with my acc no and name to save time when i pay cheques in.
Of course another 'machine' that does all the work is wcpro (or george).I did suggest as a feature that it print off all the days clean slips, but since coming up with a better idea i wouldn't use this feature now anyway.