A Death Star
We've all heard about Death Stars and imagined how awesome it would be to have one when we were a newbie to the game. Now however we are more experienced and have got to question if it really is worth getting. It can't use Jump Gates, which means it is commended to a life of snails pace misery. But lets forget completely about that, lets calculate how good it is with power and armour, compared to the miniature disruptor version, the Titan.
Titans cost 50 000 credits, and have 3402 power. So that's 14.69 credits to 1 power. Death Stars cost 500 000 credits, and have 25 500 power. So that's a less awesome 19.60 credits to 1 power.
Also, Titans have 2048 armour, so that is 24.41 credits to 1 armour. Death Stars on the other hand have 13 500 armour, which is a mind-numbing 37.03 credits to 1 armour.
So for pure power and armour, you would be much better off getting 10 Titans instead of 1 Death Star, and you would be most definitely rewarded once you have a war outside your galaxy. Mind you though, the Death Star shields make it take less damage against heavy cruisers than Titan shields do.
So really, the choice is up to you.
25/30 Spaceports
We all like trade routes, they are a great way of getting credits, but is it worth it getting 25/30 spaceports for that extra 1/2 trade routes?
Lets start with 25 spaceports.
Overall the spaceports from 20-25 cost 219 262 credits, which would take 730 hours to build on a base with 300 Construction Capacity. (yikes!) If the trade route generates 35 credits per hour, and the extra spaceports generate 10 credits per hour, it would take 4872 hours to profit. That's 203 days, 6.7 months or 0.55 years.
Now if you are brave and want to see if its worth getting 30 spaceports, take a deep breath, you'll need it.
Overall the spaceports from 25-30 cost 1 025 830 credits, (yes, you did read it right, over a million credits) which would take 3419 hours to build on a base with 300 Construction Capacity. (that's about 4 months!) If the trade route generates 35 credits per hour, and the extra spaceports generate 10 credits per hour, it would take an overwhelming 22796 hours to profit. That's 949 days, 31 months, or 2.6 years. So basically, unless you intend to play that long, stay well clear of 30 spaceports.
20/21 bases
20/21 bases, you want them because 'all the cool kids have them'. But are they actually worth it?
The 20th base costs 13 107 200 credits, yeah, that's a lot. If the base had 200 economy + 210 income from trade routes, it would take 31968 hours. That is 1332 days or 3.6 years. Of course this is forgetting completely every other credit cruncher (e.g. structures).
As for the 21st base, it would cost 26 214 400 credit. So if it had 200 economy + 210 income from trade routes, it would take 63937 hours. In case you aren't very good at doubling that is 2664 days, or 7.2 years.
So, it would only be worth getting these bases if you happened to stumble across several debris piles that happen to be in the millions, and you happen to have a hell of a lot of recyclers.
It is also important to note that you should think about more than credits when deciding on trying for base #20 or #21. A new base will increase your economy but it also provides you with higher production and possibly research capabilities.
In the end the decision lies with you.