personally, thats too fast for my taste

i usually go quite fast, but i will always have 5 light frigates plus my cap, and by the end of 3 planets or so, i will have 5 Long range frigates, and maybe 5 more light frigates... depending on the type of planets....

i like to play medium to large maps, so i expand to a point where i have a fairly good economy between all my planets, then hunker down and wait till i have the resources to build up my fleet, do research and defend my empire effectively. usually (and on the map i have in my mind) i expand aggressively and quickly enough to secure my empire (usually i expand till i reach a good choke point or 2 from which to defend my empire), then calm down a bit... then, when im forced to or have sufficient means to defend myself and have a fleet big enough to advance, i move on.

there is another map i have in mind where there is only one planet that allows you to get to the star, and then to another system with lots of resources. in that case, i expand or even jump ahead till i reach that planet, fortify it, then work my way back so i cant be seperated from the bulk of my planets.

i have to say though, the rate of expansion depends on the size and type of map... if there are alot of neutral resource extractors (i.e. in plasma clouds etc) then you can probably hold on on colonising too fast, on the other hand, if its a smaller map, you might want to focus on finding a good choke point, fortifying it, then taking the rest of the planets at leisure... it really depends on the map, the race you are playing and your playing style...

i remember the first game i played, i went to another planet with a a milita, thoguht it was the bad guy, and didnt colonise it until the end of the game... dont know how i screwed that up, but anyway, keep playing, you will figure it out.... good luck

It depends on the size of the map and what planets you have nearby.  Large, sparsly populated maps can focus on gaining more planets while smaller, crowded systems forces you to go military after your first colony. 

Asteroids are inexpensive to upgrade with with only one population upgrade while all other require two and some research techs in order to increase your economy.  With that in mind, I consider an asteroid a half colony so three or four colonies are the norm for me before I start entrenching with frigate factories and hangar bays while getting an economy up.

Try your hardest to get both done at the same time. There's a critical amount of trade ports to get that allow you to never have to worry about cash again, but a lot of times it's not a good strategy to get up to that..

Soo, i completely agree with Annatar

Never too many, as long as you don't need the space for labs and such.

I suggest getting a fleet up as fast as possible, research, you probably could fit 3 research stations or more on your home planet if you max out the logistal slots (suggest 2 military, and 1 noncombat labs) and more than likely you get most of the ship you probably need to defend and expand, either use a colony cap ship or have a large fleet to escort your colony ship. usually, I finish building up a planet, meaning, research all planet upgrades and build all the use many defense as you can, with one or two combat labs you usually build the essential, (point defense, and hangar)

On the economic side, use the noncombat research to increase your metal immediatly, you can sell the addtional metal for credits in which you can use to buy crystals

lol as for trade ports on a large map, in one system you probably could get up to 1k/sec on credits, enough to buy crystal or additional metal