[iamnotnicola]

You only seal (the expensive operation) when you add power.

Once you stop sealing you don't need to seal again for ~1 year (depending on your sector lifetime).

Keeping storage power is a cheap computation in comparison.

[jsmith45]

Assuming one is starting off by sealing pledged sectors, they would also need to re-seal any such sector upon upgrading to store actual content pursuant to some deal they have accepted.

I'm assuming there is probably not enough real storage demand yet, so large miners will end up pledging sectors a fair chunk of the time, in order to increase their power, at least while they have spare disk space remaining.