Casual Game Play?

You "can" play it every other day. However you will miss out on daily activities, daily bonus energy boosts and most probably lose arena ranks (which gives crystals for energy refreshing+purchaseable gear) a lot, which in turn makes your player level progress awfully slow if you chose to play that way.
It chains all together and creates a domino effect, slow playerlevel progress, your characters stay low level+geared, they can't stay competitive in arenas. Most important of all you would need a lot more time to broaden your character roster and gear them up for battles. If you just enjoy doing lightside+darkside+cantina+galacticwar and not too fussed about arena, it's definitely playable, but you will progress very very slowly. Is it playable and can you find your personal joy with it? Definitely.
Most players would say being topdog in arena is the only real goal and purpose of the game, but that's not entirely true. There are only so many spots in the pvp scoreboard to occupy and many players have other self-declared priorities/goals ingame.

If you're having fun playing that way then more power to you, but if you're the competitive type who wants to rank high in arena it's not going to work out. Free-to-play players have to work (play) extra hard and smart to maintain their rank, at least I do on my shard.

I wish I could tell you that any given toon will have staying power but the mainstays of only 6-8 months ago eventually lose their effectiveness, with some exceptions (Chaze, DN, Rex). But periodically toons who fall out of use suddenly bounce back into the spotlight so I hesitate to say that upgrades to mid-tier toons are a waste. It's part of what makes the game fun.

Other than arena ranks, you never lose progress in this game. That makes it worth while for the casual gamer. You can play at your own pace. Some other games you can never get anywhere without spending lots of cash or playing 24/7. Naturally the more you play the more progress you will make

Ok, thanks for your time and your responces. I suppose I'll play for a little bit and see how it goes. If it stops being fun (which I'm suspecting based on your comments) then I'll stop. Just looking for a nice timer killer/mind rest. Wish there was more story in single player, like Star Wars Assault Team had.

Actually, TheBigHert, the game is very fun to play and quite addictive. But, the other commentators are correct in that you will get out of it what you put into it. Fun? Always. But is always losing and very slow progress fun? I don't know. I could play a game a little bit every day or two days and still have fun, but it would take a long time to complete. This game only has to be played every day if you really want to dive deep. Otherwise, play any way you want. It is just a game.