I do it every game if:

It's a close game
I have time

It takes me about 20 minutes to really get a feel for the other team.

If it's a user I gameplan but if it's a sim I stick with the previous gameplan.

I think anyone who doesn't customize their gameplan every game come tournament time is at a huge disadvantage.

I would like to see a feature where you can change your team/player game plan for the next game only, and after that game simulates it automatically goes back to your previous settings.

When I got my first team, I game-planned every day. Now I have too many teams for that. I change +/- settings every game (if needed), and check whether to double-team, but I try to set up a depth chart and distro at the beginning of the season, give it enough time to see how it's working, and then tweak as needed to try to optimize my own team. In-season, all I really do is check every few games to try to make sure I have the optimal combination. In the tournament, start actually looking harder at the individual games, and I gameplan every night. Well, at least if I have a good team. If I'm in a rebuilding year and slip in as a double-digit seed, I don't pay quite as much attention as when I have a title contender.

I only have one team, so I try to game plan every night, if I can. I work late nights so sometimes I miss one.
I am thinking about backing off a bit. I think by doing too much game planning, I don't always give a lineup a chance to see if it is the optimal combination. If I were not so cheap, I'd get a 2nd team that I am less vested in so I could experiment more. With having only 1 team, I get too caught up in not wanting to loss ANY regular season games...which probably keeps me from taking a chance on certain combinations of players and strategies.

Bob you arent from indy are you?

Every day, every game. The way I see it, if I'm not going to devote the time to play the game (and that's basically what setting your gameplan is), why pay for the game? I've got a defensive positioning formula I use with each of my teams that sets my +/- positioning...I glance once at team stats to make sure there's no anomaly that calls for me to adjust what the formula calls for. I update my spreadsheets with stats from the previous night, look at my opponent's tendencies defensively and adjust distro up/down and 3 pt. frequency up/down for players and tweak starting lineups based on the new data. Four teams, four worlds...if they all have games (rare, I've staggered them so that at least one world is almost always in recruiting) it takes maybe half an hour total during the day to set up for that night's games.

I think I've kind of fallen into a bit of a funk in terms of game planning since both of my teams play in sim heavy conferences. I will game plan for the toughest matchups and for the NT but otherwise I tend to let it ride most of the time, only changes defensive settings. I've found a couple times that I've let my game plan sit for so many sim teams I haven't even adjusted for player development.

I gameplan everyday except against the easier Sims.  I'll even game plan for those if I have a rebuilding team

I game plan for evey game, maybe that's my problem. Lol

Halfakracka, not sure I understand the reference bro.

I'll usually just switch my defensive setting against sims and in many not-must-win games.  Tournament time is different where I'll study the other team and adjust everything if need be

I gameplan most of the time. Don't usually gameplan against sim opponents in my conference unless they're performing really well. 

I will say that if you are one of the ones that never game plans against a sim, that is fine, HOWEVER ... you then sorta lose the right to complain if the sim upsets you, because you gave up your big advantage over them.