"Rob
I don't bother as I would rather have designers and I want to replace every part, every race except the engins where I replace them every 2 races..
I have nearly 200 mill and that is after I've wasted money by messed around changing staff and so on... Commerce is not really needed tbh.. but that depends on your personal setup.. I know I am not the only one without commerce and I also know that you are not the only one to make over a mill each race... so it all depends on preference.. but I did aim that at new managers.. esp the ones who have not figured out that they are paying more for the commers staff member than they make... ooops. I've given something away there. ;)
Commerce is at level 5 and Conner is level 2.. So he doesn't need to have a staff member taking £1000 per race from him. ;)
You can still have enough designers and replace every part for every race and make almost a million in commerce... It just needs a lot of testing with your commerce to establish which prices and margins give the maximum amount of money. I took me a lot of testing but I give maximum priority to design and replacing parts every race as well and make a bunch of money from commerce. So I think it is worth it... In the end though you will end up with a bunch of money and no way to use them! :P
So if everething else is in place and there is some profit then yes commerce might not be needed in the long-run... I have 850 million and it doesn't help me be faster than if I had half of it.