So import from the return that is the most complicated or has depreciation or carryover losses or credits.

I hate to mark this answer as helpful...

I'm amazed that TTax is so unhelpful in going from joint to separate or vice versa.  Should be able to enter all data as his/hers (or his/his or hers/hers) and have TTax calculate both ways.  It's not hard, just takes a small commitment to customer service.

TurboTax requires a re-subscribe payment (this year) to get my spouse's tax return documentation from last year. And then you don't allow account mergers for joint filing. This is basically a hostage situation.

I agree.  Merging info from two returns should be a basic function of Turbo-Tax.