Minimum contract lengths for suppliers/partners

I suggest that a minimum number of races should be implemented on contracts with suppliers for tyres, fuel, engine etc. 

This would be especially welcome when/if the suggestion I posted in http://igpmanager.com/play/?url=forum-thread/3790 
gets implemented. 


Reason for a minimum contract length would be that a manager should not use the various engines or tyres as car setup for each track but would have to live with a better car on some tracks and a not ideal car on other tracks. This should help into making the game more strategic and force managers to put more effort into making strategic as well as operative decisions.

What the minimum contract time (that would not be possible to break) would be, I let the admins decide, but personally I would like to see contracts for entire seasons or maybe possible to change ones during every season plus between seasons. 

Well, is it a problem now? I don't see lots of people changing from the ideal suppliers, so I'm not sure if this will change anything.

Jaap: I quite my post above:
"This would be especially welcome when/if the suggestion I posted in http://igpmanager.com/play/?url=forum-thread/3790 
gets implemented. "

The only issue I see with this is if someone changes leagues - and thus, schedules - during a season. If seasons stay as 17 races, and someone leaves a league that's done 8 races for one that's done 4, does the manager have to sign a new contract for the remainder of the season in their new league, does the contract immediately terminate, or automatically extend?