If you think you will do investment and trading together then that is totally up to you which needs good amount of financial support. If there is good financial support you can invest in any one coin for a long time and carry out your own trading activities in all other coins.
I think this should be the best thing to do because depending on just one source of income isn't always safe. If we can do both trading and investing. It'll benefits us because when you trade and make profits, you can reserve some profits and use them to invest into Bitcoin or other altcoins that you're interested in although it'll be better we Invest in Bitcoin because that's the most safest cryptocurrency you can invest in and be sure you can make profits in the bull market.
Trading needs your active awareness because you'll have to be active with what's happening in the market to make your trading very profitable but investing doesn't need you to be very active in the market as you can just buy and hold and wait for the bull market, so both are combinable.
According financial support or not to make choose between trading or investment, have other factor beside with good financial we have another income and trading in cryptocurrency is not our main income. Simple if you have much saving and have main job with higher salary payment every month will choose investment than trading, but without have another passive income and trading is the only way for our income there are not any choose except prefer trading than investment.
In trading need skill and always updating bad or good news every day, difference with investment we close all market price update in daily day and waiting when price going up few weeks or months later but in trading we must active for getting good news and selling assets trough have profit.