Some tires, particularly tubeless-ready, are nearly impossible to mount. I won't share my horror stories, you can just relive your own .....
I have a pair of very strong tire levers (which double as quick-link pliers) and I often carry more than three levers. Some tires loosen up over time.
As for tire pressure, lower pressure usually means more comfort until the tires start flopping or pinch-flatting ... and slightly softer tires actually run faster than super-hard tires (by margins so tiny only racers and fanatics even care.) But I generally run my front tire softer because 2/3 of my weight is on the rear tire, and the slightly softer tire does add a little bump absorption and possibly compliance on corners.