All told, the desk and filing cabinet took around six months of evenings and weekends to complete. I didn't keep track of exactly how many hours it took - next time... The blog postings about it have taken rather longer... :-)
As for the cost, after the initial outlay for the materials, there was a stream of extra purchases - the dowel jig, a set of forstner bits, extra reels of edging strip, two tins of danish oil, etc. I didn't keep track of all the costs (next time...) but the total must be somewhere around £350-£400, which is less than a third of the cost of the estimate I'd had from the professional furniture maker.
I haven't paid myself for my time though. If I had, and I'd paid a reasonable rate, that would surely have made the professional route cheaper.
It's not constructed as well as the professional would have done it either, though you have to look closely to tell. It's by far the most professional-looking bit of DIY I've done.
There were moments when I wished I hadn't started it, but not too many. Most of the time there was good progress throughout and few hurdles, which made it easier to continue, even in the early stages when the end seemed a long way off.
The end result is immensely satisfying - it's exactly what I wanted in terms of size, shape, colour and texture, and best of all I made it myself.