Taxable account.
I read here often that people do rebalancing on regular basis in their taxable accounts.
You sure about that? The only way I ever intend to rebalance in my taxable account is through new contributions (during my accumulation phase) or my withdrawals (during my drawdown phase).
Otherwise, rebalancing in a taxable account will in general incur capital gains*, which is stupid if your retirement accounts are big enough that you can achieve all your rebalancing needs there instead.
*It is possible that you have two or more funds in your taxable that both have unrealized (and unequal percentage) losses. You could sell one and buy the other, achieving your rebalancing and incurring capital losses, not gains. However, given enough years of steady investing, this will occur less often and with a smaller proportion of your account, because given enough time your oldest shares will have massive unrealized capital gains and will comprise of a majority of your portfolio's value.