would you upgrade 1.21 to 1.50 ?

update - SHOICKING!

Yes - my ring has a GIA cert. It was from the year 2004. The stone table is a 7.2. That is on a 1.25 carat. "I" color, VS1. It cost $7990 for just the stone. Jewelery store has a buy back program. They claim to give you back exactly what you paid for the diamond. Obviously not the current price a diamond with those specs would cost 10 years later. The jeweler showed me a 1.50 stone with a 7.4 table and exact specs. I could see no difference whatsoever between my original with the 7.2 table and the bigger 7.4 table.

Here is the clincher: It would cost $11, 000 more! But he'd give me a nice discount and would only be $9,000 more! LOL! Can't even see any difference between 2 stones.

I was contemplating if I only had to add $4000 or $5000. So I ran out of the store as fast as I could. BTW, my stone looks bigger anyway since it was reset into a HOF significance style halo in year 2010.

So now instead of an upgrade, I am exploring (revisiting ) tennis bracelets for my birthday present in the $4,000-$5,000 range.
The minute difference is in the depth. 1.5 ct should be around 7.4 mm while 1.2 ct should be around 6.9 mm. Since your current diamond has a bigger spread to begin with, I can see why the upgrade has no appeal to you. Save your money for the tennis bracelet!
 
I would not bother. I can see upgrading from 0.8 ct to 1.50 ct, but not from 1.22 ct. The size difference between 1.21 ct and 1.50 ct is not enough for me to go through the trouble and expense (reset fee and possible new setting).

Another important point is that you will lose a lot of money from the trade. 1. Your 2007 price is likely much lower than today's price. You may get more money by selling the diamond yourself. 2. The price for 1.50 ct nowadays costs a lot more than in year 2007. It is a double loss for a change that is not readily noticeable. Not worth it. I would upgrade only if the new diamond is 2 ct or higher.

This. The spread change isn't enough to warrant that increase but the trade price is going to kill you. Diamonds have SKYROCKETED since 07 and your current stone is worth significantly more in trade than they're offering.