Minute marks for fleet capacity upgrades?

The idea of setting a fixed time for committing to fleet upgrade capacity is a silly one, it ought to be decided by strategic considerations during the match - the reason this question even came up is because in the single player game the AI is not challenging enough to force you to build a bigger fleet. In multiplayer it is not viable to sit on a pile of cash - you simply must build fleet, now, or be annihilated. I suggest you try out multiplayer or, if you wish to stay in single player, you challenge yourself by setting a time limit for winning the game. This will force you to build more fleet faster and earlier. This game is best played under pressure.

When to upgrade fleet supply is probably the most strategic decision you make during the game. Do it too early, and you're economy will be weaker than it could have been. To late, and you may get steam rolled by someone who upgraded it sooner.

As Hyrim says, there is no consistent time of when to upgrade. As he says, sitting on a pile of cash means you're not putting all of your resources to use, so if you start accumulating resources faster than you can spend them, thats a good time. And even if you don't want to attack anyone (and you should, a fleet that's just sitting their isn't a very good investment), you'll need enough ships to counter whatever your foes can throw at them, so try to always keep as many ships as your opponent has. But beyond that it really depends on the game, your opponent, and how good you are at judging the situation and determining what it calls for.

Depends.  I could go second fleet off the bat if im not going econ, or if im rushing multiple caps.  Usually if you are on the front u get first upgrade right away, and then only upgrade if you hit the cap and have income to build more ships.