Should one always have a plan? An actual reason for every move (other than eg "protect this piece" or other obvious urgent moves)?
It's not that you should always have a plan in the form of a number of moves that you happened to like more than others, as that's in the neighborhood of Woodpushing 101.
What I mean with a "plan" is, perhaps, what could be considered some kind of strategic improvement of your position (or the worsening of your opponent's position) that's not merely some kind of immediate obvious gain (like material gain) or an urgent move (eg. defending a piece that's in danger of being captured with no or too little compensation). In other words, how to improve your position in the long run (ie. more than just a move or two) in a situation where there isn't anything absolutely urgent going on.
Examples of such "plans" could include things like:
- Noticing that one of your minor pieces is not doing anything relevant and, eventually, getting it to a position where it's actually doing (or could potentially do) something more useful.
- When one of your minor pieces is trapped behind your own pawns, getting it free and making it useful (a special case of the above).
- Mounting pressure on a weak enemy pawn (even if there's no immediate obvious way of capturing it with gain) tying enemy pieces into defending it, away from attacking you.
- Improving your king safety, or weakening the opponent's.
- Trying to open a file for your rooks.
Perhaps another way of putting it is that every time you make a move, there should be a reason for that move. You should be able to explain why you made that move. A reason better than just "I couldn't think of anything else", or "it felt good".
Should one always have a plan? An actual reason for every move (other than eg "protect this piece" or other obvious urgent moves)?
It's not that you should always have a plan in the form of a number of moves that you happened to like more than others, as that's in the neighborhood of Woodpushing 101.
What you should try to do is to understand, by analysis, the activity on the board for both sides. It goes like this: No activity -> activity -> threats -> initiative -> unstoppable initiative -> checkmate.
Going from one stage to the next one usually involves more than one solitaire move, and those moves happen to be called "a plan".