Keep in mind that if you only have exposure on one sector and you only own a small number of stocks or assets, then it will only take a relatively small amount of time to actively manage it and rebalance it. Otherwise, if the numbers of any of the elements increase, so will the time required to successfully and profitably run it. One of the key elements of passive investment is that at least a majority of positions are bough with the idea of holding the assets for a long period of time (trades can be exited if conditions change), this allows for the overall experience of managing a passive investment portfolio to be considered straightforward. Unless market conditions are extreme and hard decisions need to be taken actively, then I would venture to say that a privately owned portfolio with a small-medium size can take around 30 to 40 minutes a day to be managed. Please note that this might be time consumed during the day and not a full sitdown of 40 minutes.