The pension credit applies to $2,000 per spouse in applicable income. It's not huge, but is one of the things that helps reduce the tax rate in retirement.What is pension credit? And what do you mean by optimizing capital gains?
As for optimizing gains, I mean simply that I can manage/manipulate income in retirement. This is because my base income is low. So if I sell a holding for a significant cap gain, I forego melting the RSP that year. Or vice-versa. I do this with an eye on the tax brackets.
The upshot is that as a retired person I can optimize when I pay taxes in order to minimize them.