Most know already, but maybe helpful for "some" new players & MRRacers.

A car in red conditions has a button for reduce service-time / maintenance with 30% by watching add, after push & watch this button disappeared, only GC or M$ / R$ possible for reduce more. But switching back to menu and then go back to that car & track shows this reduce add-button again. Watching in this way six times a F1 is ready for playing further, need less than 5 minutes. Good luck. Greetings. Dieter
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1st : available

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2nd : Button disappeared

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3rd : back to main menu and then back to series / car / track : button returns !

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with 5th repeat comes the JUMP OUT button :

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Ready to play !

1 is from 3 hours to 2h 05m,
2 is from 2h 05m to 1h 27m,
3 is from 1h 27m to 1h,
4 is from 1h to 41m,
5 is from 42m to 28m,
last is jump out 

EDIT : title topic changed without ", because no hyperlink possible !