This is one thing to consider when you are deciding whether to bomb a factory; if the factory will soon be yours, don’t bomb it. More to consider;
If the factory is seriously damaged, abandon it, don’t repair it.
Certain repair levels are highly inefficient to bomb. A factory with 2 damage of 6 damage still risks the bomber but only costs the target $4.
A factory with 6 of 20 damage needs more than 1 bomber, but less than 3, which means he has to over or undercommit and take unnecessary risks.
If the target repairs the factory fully, it just gets bombed the same way the next turn, which wasted $6-$20. Use your excess capacity (Russia @ 19 units, Germany @ +29 units with captured factories) instead
Especially with Russia and Germany, choosing in a cadgy way how and when to repair can complicate your opponents choices. Still, they should be able to overwhelm Russia (with bombing and attacking), nevertheless, don’t make it easy.