I've seen everyone and their mother talk about ways to max a planet out. What I don't understand is why everyone wants these super high stat planets when the loss of one of these +18 planets would put you back so severely. Having gotten past rank 250 before setting foot on the forums I had been utilizing a totally different strategy for my planets in which I was/am still only raising my worst value planets first in an attempt to lower the effect of a single planet loss by spreading out my resource gathering. Is there something I'm missing or some reason not to do this? Does the "math" say the risk of loss is not enough of a factor?

Well. Lets say you start with two very massive/average gas.
If I get 10 terraformers what can I do with them?
Option 1:
Planet one:
10 terraformers.
3x mega rich. 3.75 multiplier.
Planet 2:
0 Terraformers
Average. 1 multiplier.

Now, if I put 24 points of produce on...
1:
24x3.75= 90 base production.
x2=180 total.

2:
24x1=24
x2=204 total.

Option 2:
Planet 1:
5 terraformers
Extremely Rich 2.5x
Planet 2:
5 terraformer
Extremely Rich 2.5x

24 on each again...
24x2.5=60
x2=120.
24x2.5=60
x2=120
Total: 240.

You actually get more by spreading them out.

While it is true that increasing your worst planets make them less likely to be taken, it's a question of how worth it it is: if you don't have any planets that are particularly worth taking, are you really doing all that well? Besides, for me at least the fun is to make planets like that, having a lot of normal planets seems boring.

Oh they're "worth taking" I have a few +2's and +3's, and even one +5 but the loss of one wouldn't hurt as badly. Having just done a scan blitz though I can see a +16 and a +15 (well defended but still tamable given middle of the night raiding style I'm used to doing). The loss of those would probably seriously hurt their owners (and paint a two day target on my head) but a loss of one of mine would only set me back a tad. I still have decent income so that's not an issue so far as I can tell from others who have posted theirs at around my rank.

Well, if those are Toxics you're talking about, then from my experience you don't have much choice, I've already maxed out most of the Very Large Toxics I've scanned.

the formula that determines the cost to settle a planet has a cube function in it. It gets expensive so eventually quality is going to matter. If you had more 15x mega rich toxics than you could possibly want, you wouldn't be too happy about all the volcanic planets you had settled. That, and artifacts are pretty much the only thing that matters at the end of the game. Binaryman could make 15x mega rich toxics untill the cows come home and it could still not be a very good idea since his mining probably fills up in a few hours compared to research and raises the price to settle more artifact planets anyways. There might be some ideal ratio of mining and research (for the purpose of credits) that you'd want to support however many planets you will eventually be able to settle, but it can always be lower and it can always take longer.