So after four years of sharing an apartment, my roommate is planning to move out into a place of her own with her boyfriend.  I have not had this experience before, and obviously a number of issues have arisen.  I was hoping to pool the general body of thought out there, i.e. you kind friend, for any tips you could give me or your opinions on the following items which I am undecided about how to proceed:

1) Our couch.  That's right, we bought it together.  I am perfectly happy to buy her half from her and she is perfectly happy to let me.  The issue is what value we place on that half.  The couch is now 4 years old, but she is quick to note that we've kept it up very nicely.  Do I value it at what someone ELSE would be willing to pay for it (and no one on CL buys furniture for more than 800, right?), or do I value it a bit higher based upon the fact that it's mine and I like it and I know it's in great shape.  We originally bought it for 1000 and change (it's a very nice L-sectional).  So I was going to offer $450.  Is that crazy?  My bf says I shouldn't offer a dollar over 400, but I think the roomie is hoping for some extra padding to help with her moving expenses.

2) My roommate is not willing to pay rent on two places during the same month.  But doesn't this mean that she's only going to be able to give me 2 weeks notice once she finds the place of her dreams?  Is that unacceptable, or is that standard?  I can probably find a another roommate in 2 weeks, but will they be able to move in on such short notice?  Basically, I'm just wondering what's the standard protocol.  Do most people settle on a move-out date, or what?  obviously my roommate clearly would not be happy if I gave her a deadline to move out by.  But at the same time, if I only get 2 weeks notice, how can that possibly be fair to me?  

3) Interviewing roommates.  I have no experience with this, so if anyone has any quick tips on things to look out for or clever questions to ask, I'd appreciate it.  

Hope everyone has been well!
Gaelen