TOC - I've played it maybe 50 times, but not recently. I've only ever played it with locals and what I've learned is that whatever shot you play, good or bad, your partner (s) will recall, 'Arnold Palmer played from there in 1960, except that he used a 7-iron,' or, 'I remember so and so shanking it from there and taking a 7.' It was very heartening when you found that you had done better than someone famous, on one hole or another.
I recently played a Seniors' match away at Bramall Park, a course I played a lot in the 1980s, maybe 100 times. I was horrified that I was hitting 5-wood into greens that I used to hit with a 7-iron or 8-iron and we were playing from forward winter tees.
I played a Seniors' match today at Wilmslow and we played from the forward, yellow tees. Although I was still short off the tee in comparison with my playing partners I was, none the less, hitting the ball from the yellow tee to where I used hit it from the white tee. So, in my five years at Wilmslow I've lost 30 yards from my drive. But at least I got to see bits of the course I haven't seen for a while. I didn't score any better than I would have done from the medal tees because I still had to lay up short of cross-bunkers etc - except I was laying up with a 7-iron when from the back tees i might lay up these days with some sort of hybrid.
I have been a member of Conwy now for some 30+ years. The design has changed little in those years, but conditioning and so on have changed. My ability has declined, but I am less scared of the course, and the gorse in particular. I don't drive far but I am driving straighter (thanks to new technology) and by keeping the ball in play my scores are not that much worse than they might have been 20 years ago. The good thing is that Conwy is still receptive to the ground game. Even if I top a shot it will probably run almost as far as the aerial version and a running approach to many of the greens is still very much on the cards.
But someone earlier mentioned the bad shots. I have awful days nowadays when I can't get out of my head a shank here, a topped shot there, failure to get of a particular bunker or driving out of bounds on another hole on a previous occasion. I had been driving perfectly straight today and stood on the 7th tee with an out of bounds hedge and road on the left. I used frequently to slice (left-handed) onto the road here. But as I made my backswing a thought came into my head, 'You don't fear the out of bounds any more.' What a silly thought! I didn't hit it out of bounds, but my grip tightened fiercely and I tried to steer the ball as I struck it. OK it went straight, but I played first on the next shot by at least 75 yards! There are advantages and disadvantages to knowing a course well, provided you have the technique, physical prowess and mental resolve to overcome the frailties of the ageing body and mind.