Kevin
Early in the game when you're levelling up quickly it's not cost effective to keep upgrading CDs, especially seeing as the first few seasons you're not usually competing against many other managers. In my experience most of the teams in Rookie the managers create the team, get bored, rarely set up and leave AI to manage the race. If you're active you hould beat most of these and gain promotion quite quickly.
Yeah I made 1st-2nd in every single race of the season. Quite boring, but it didn't bother me too much because I saw it as a chance to learn the basics and earn easy money and XP. Now I received a couple of invitations to join other leagues, but I don't know what would be more efficient:
-Keep playing the same abandoned league and, assuming the Pro divisions managers aren't active either, keep earning easy money.
-Join an active league, get way worse results and hence less money, but more XP because I'd be racing against more experienced managers.
Kevin
Anyway, the best thing to do early in your iGP career for CD and TD is to not bother about upgrading until the break between seasons. Then during the break hire a new CD the same level as your team (and a TD if you're interested in maximising research the next season). Then you leave and re-join your league during the break (before race 1). This will result in your car being reset as if you had this new 5 star CD for an entire season.
Personally, I always let the Doctor contract expire and make do with the one that the game auto-assigns because the wages are so much lower (only £50k per race). Yes it will slightly reduce the effectiveness of driver training but IMO the cost saving more than outweighs the reduction in speed of training.
When you get up to the higher levels (18+) you level much more slowly and it's worth hiring multiple CDs to optimise your next season design.
Yeah I'll leave the default doctor, since I won't have any decent driver in a while anyway. As for the CD and TD, I guess I'll take my chances and hire new ones before the next season begins, regardless of what league I decide to play. I hope I don't end up broke.
Thanks to both of you for your answers!