That PC is used by whole family and I have no intention to change anything about the routine how it's used (most of the day it's powered off or suspended), just to use the time when someone is using it.
When running 24/7 it will give about $1 per day of revenue and perhaps give back about $0.50 in profit (at current difficulty and exchange rate, using typical U.S. residential electric rate of $0.15 per kWh).
If you run it four hours a day, that's about eight cents a day in profit.
The days for casual mining are pretty much over, sorry.