Every RC Forum has a 'How long does it take you to build a kit ?' post.
I have just spent two hours building another stripboard Arduino, if I stuck to one design I am sure I could get it down to about 15 mins.
Whats your average ?
Any tips for getting your build time down ?
Duane B
Whats your average ?
About three months for a project. Some have been done in as little as two weeks and another took three years.
if I stuck to one design I am sure I could get it down to about 15 mins.
One thing I have found is that if you try and rush you make more mistakes and it takes much longer.
Any tips for getting your build time down ?
Try and build it in your head before you try with real components. Get all the parts before you start making.
Depends on how complex the project is.
The '1284 test board at my signature link didn't take long using wirewrap sockets.
That's what I keep meaning to do - add a 2nd one and try running both off the same crystal ...
Well, first you have to define "finished".
I made a wall plotter that made cute designs with old steppers. I could call that a finished project, many would. However, I then decided that I wanted it to print and draw shapes. Then I decided it should be able to handle Postscript. The "finishing" point I am now considering is mounting an infrared laser of a couple of watts on the head, instead of a dry erase marker.. making it a laser engraver.
The original wall plotter was about two days (while the kids were at school and in the evening), but the final laser engraver.. well that would be over a year. What's "finished" to one person certainly isn't what's "finished" to another.
The nature of Arduino, as well as the nature of we who love to tinker with them, is that "Finished" is a term we don't use often. We can't leave well enough alone long enough to tie a bow on most things...it's always a case of "but if I staple the cat to it, then it will meow, too!" thinking.
There are always more staples and cats.
I'll let you know if I ever finish a project 
Rob
focalist:
...it's always a case of "but if I staple the cat to it, then it will meow, too!" thinking.
I feel a video of a quadcopter coming.
And it depends on what you define as "make a kit". The Blinkenlight kit took me roughly half a year. But the outcome was an actual product. If I take one of these kits and assemble them this is significantly faster 
Three projects that were collaborative with others had a definte delivery deadline - they took "all the time that was available". If we started the project and it was 2 weeks to "showtime" we spent 1.999 weeks on it, calender time. The amount of man hours .. dont want to think about that .. but the usual exponential curve with hours/day as dead line approached. These projects have been between 1 week and 1 month.
My other projects seem to get stuck at the 85% or 95% complete - usually a case of finish the coverbox, or make it a little more sturdy for moving about, or replacing the glue with proper screws. The small projects take 3 days - but two projects are in eternal POC, tweak and redesign now for the 2nd year.
So to answer the OP - any number between 2 to 2000 hours.
Tips for reducing time? Let me ask a contra-question: Why? It is my hobby, I do it for enjoyment, why shorten it? OK, producing more finished project to show off to friends and family would be nice, too. ( Hmmmm-- food for thought. )
I'm with Msqaure, if there is a deadline then the project will take exactly as long as you have, with the workload starting with 9-5 days and plenty of real lunch breaks at the nearby al-fresco cafe; increasing to lunch at the desk, pizzas ordered in, all-nighters and all-weekenders as the deadline approaches.
Personal stuff never gets finished, I stopped working on the digital speedo I made for my truck the day it displayed the correct speed three years ago, it still doesn't have a face plate and half the buttons do nothing as I couldn't be bothered adding the fancy features once it worked
Rob