Is it always beneficial to meditate?

If one has a regular meditation practice and has no particular mental health issues or physical health issues - is it always beneficial to meditate? Or are there circumstances or points in time where it might be better to stop or cut back? I ask because there are points where in my practice it just seems impossible to meditate and I have stopped for a dew days or a bit longer. Is that a mistake? Should you just grit your teeth and meditate anyway even if the meditation session is pretty unpleasant?