My front deraileur needs adjustment after every ride
Sounds like you are getting slack during the ride.
This will happen with new cables but if you get it every ride something then else is going on.   

My thought is that your barrel adjuster is not holding.
Does it look like this?  

  

The barrel adjuster should have a lock nut or something to hold it in place.
Mark the position with tape or a marker and see if it moves during the ride.  

The M 191 is a lower end Shimano but you should certainly expect much better performance than this.

And congratulations with getting up to 20-25 miles a day.