Very occasionally I'll have a look to refresh my memory. For example there's a great little lane off the Clitheroe side of Waddy Fell I needed to check last year.
Through Kitchens, up to Cow Ark - I like that one and usually ride it a couple of times a year. We did it on the Forest of Bowland forum ride last year.
Another one I like is to start to head N from Cow Ark towards Whitewell but take a right onto the lane heading NE towards Newton. Cross the B6478 just above Newton and carry on NE to rejoin the B6478 over there. Take a left and drop down into Slaidburn.
I know my local roads well enough but the area I cover is wider than my detailed knowledge so I plan precise routes and create GPX files for me and other riders to use. I like there to be at least one other person with the route on a GPS for backup. We usually stick to the exact route planned except when something prevents that.
We had the emergency services block one road once because of an RTA on our route so we had to improvise a diversion. I have whole-GB OS maps on my phone at all useful scales so I can quickly use those to work out alternatives. It has happened a couple of times due to major roadworks too. It is normally possible to sneak through, but I came across one case where the road had ceased to exist and was being dug up to create an industrial estate. In Devon, the route of an old road had been turned into new quarries, and the old quarries into a new road!