Worth me to sell or continue mining?

I need some opinions. I have a lot of older graphics cards and I’m not sure if it would be worth me to sell them or if I should keep them and continue mining with them. Any opinions? These are the cards I have:
5 R9 280x
1 GTX 980
1 GTX 970
3 R9 390
1 R9 270x
I was already offered 300 bucks for 2 280x’s and am not sure if I should take that offer.
Just wondering If you guys think it would be a good idea to sell off all older cards and wait for the new cards to hit the market.

Here is my suggestion… Set them up on a rig and set it to mine on nicehash. For 3 days make a note of each gpu’s daily profit. Take the average of that number of each GPU and divide that into $$$ offered for each card. That is how long it will take you to make the same $$ not counting power

Will do! Very good thinking