I am not saying they where never used, just the fact that much of a project is scraped at one point or another. EX: Bingo card creator started as a java app, and now it's a pure webapp. He still let's people download the app, but it's on the way out.

It may be a semantic argument, but basically if the same people / team are working on the same problem then a complete rewrite does not make a new project. As far as I know zero of Windows 3.1’s codebase made it into Windows 7. However, when you look at API’s it’s hard to call the Windows 3.1 to ME family a separate project from the Windows NT to Windows 7.

I suppose it depends what you mean by the final product. I would define the final product as something that is installed somewhere and is used.

Ultimately, all products will be scrapped or superseded but to say that means every bit of code you have written is unused seems a bit odd.

True, at the same time the is a fair amount of really old Unix code. Still, length counting a temperarry bug fix that lasts a week as having identical value as core functionality that lasts 30 years seems to miss something.

A more reasonable metric might be, how much of the code you wrote today will still be in use in 15 years. And if you think more than 10 lines per day is going to make that hurdle, I think your fooling yourself.

Few programmers ever work on something that'll still be in use 15 years later. Just have a look at http://en.wikipedia.org/wiki/Category:1995_software (which isn't complete, obviously) - I don't think that even MS Office still contains much of what was in it in the '95 edition.