I've had increasing trouble evacuating, but I've recently discovered something interesting that may or may not be useful to others. I hope it will.
I use vitamin C and magnesium citrate to help the process along, but even with that, I found I was having trouble and that made me feel --- STRESSED, ANXIOUS. I would focus on the act, wait, and it wouldn't happen, and I'd end up hurrying the process and using force which is not good on many levels.
Recently I discovered by accident that if it's time to go, I've eaten my morning steel cut oats with many additions, taken my magnesium citrate, it's an hour or two after and I don't feel an urge.
If I sit on the pot and attend to something else like writing an email or reading something interesting, suddenly things will move along as they should and I even feel a complete evacuation instead of partial as happens when I strain. I'm not there yet in that I always remember to do this, but I'm working on it.
I think this may apply to other issues as well, like digestion and meds working optimally. Anxiety and stress are not our friends.