Hi, Jay.
There's a fundamental difference between an accounting/bookkeeping/checkwriting program - such as Quicken - and a tax return preparation program - such as TurboTax. Accounting principles evolve slowly over decades and centuries and an accounting program can continue to meet our needs for several years. But tax laws change daily and last year's tax program can't be used to file this year's return.
So when we do upgrade our accounting program to a newer version, we probably want to remove the old version - and recent versions of Quicken automatically uninstall the prior version while installing the new one. But we very well may want to keep several years' versions of TurboTax installed, just in case we want to reload our 2004 return, for example, to see how we reported something.
Personally, I have a TurboTax folder and, within that, I have two subfolders for each year: one for that year's TT program (\TurboTax\Tax04, for example) and one for the data that went into that year's return so that I can reproduce the return if I need or want to. Since I also prepare returns for a couple of relatives, their data is also in \TurboTax\Tax04Dat, for example. When I start my '05 return, I'll install the program in \TurboTax\Tax05 and run it from there, importing prior data (name, address, SSN, etc.) from Tax04Dat and current year data (income, expenses, capital gains, etc.) from Quicken. The completed '05 return(s) will be saved in Tax05Dat.
Meantime, my Quicken 2006 Basic is working with my QDATA.* fileset which contains data from 1990 to date and totals about 30 MB now.
RC