Hi @USDxxJPY,
It’s a bit tricky to answer your question. In short, it depends on how serious trading in your life.
Trading is a job, side-job or a “game” for us. When you are running a business, you need to dedicate your time and focus to make it work. The same thing applies to trading. When you have business, you are working hard to find customer / clients. On trading you are working hard to find various methods to trade the market. The more methods you have, the more profit you will have.
Example you trade only USDJPY. More instruments mean more opportunities. More opportunities means more pressure, effecting your psychology. You need to upgrade yourself to manage it. All of these, need time.
More method and more instruments mean more time is needed. So, if you trade as a job, you take a lot of time a day. Otherwise, it should be a side-job or hobby.
For me, I’m using 20 monitors to trading, monitor a lot instruments. I have to make plan for tomorrow while executing current plan. It takes a lot of my time.
Example on Sunday, I need to research economic calendar for 1 week ahead. I need to make plan according to the news. I need to analyst chart to find instruments to trade for a week ahead. I takes hours, mostly 3-6 hours.
When I trade stock market, I need to get information, such as finance reports, corporate action, IPO, etc.
During weekday, I have to monitor the price, when there is particular news to trade, I will collect data to forecast the result to mitigate price movement. It takes 1-2 hours for each event each instrument. Luckily, with the help of AI, it can be a lot easier.
When I trade technically, I need to monitor price movement. You will need this when your profit target is above 500 USD at once, it’s no longer a game. For example today, I monitor market the whole day. I did few scalping for almost 18 hours.
So, all depend on how do you think trading as for you. I believe most BP user is not a full time / serious trader, so you will have different answer. 
Please be careful with the illusion of successful trader, making money while sitting on the beach. When you trade for living, it means big money. You will easily get irritated by looking at your account, example you are having floating loss 10k USD. Can you still be smiling, ignoring your account do other stuff ?
Or you are naturally monitor the price, preparing plan A, B, C … etc Can you imagine, trading such big number without even care your internet connection? You have to find somewhere with solid internet access, with backup if possible.