In simple single engine aircraft with one vacuum pump the problem is not too bad.
At most cruise altitudes you will only have a 5 or 10 minutes before you hit/land on the ground anyway.
From my ATPL studies I remember that the gyro's should remain usable for 30 minutes in commercial operations.
I had a simulated gyro failure after take-off followed by airways leg, followed by ILS approach all partial panel. It shows that it can be done but it wasn't easy.
As UV has indicated, It is the gradual failing of the gyro instruments that I don't know how I would handle in real life.
I would like to at least be tested in a sim to see how long it takes me to get the aircraft inverted
FIS.