Even as long time investor there is no guarantee that you are going to make profits from your bitcoin investment, if profit is guarantee people wouldn't be scared of investing everything they have into bitcoin rather long time bitcoin investors has hope of making profit in the future since the price appreciate over time, this reason of nothing been guaranteed is why investors are mostly told to invest in bitcoin with money they can easily afford to lose.
Investing wisely is very important because even though Bitcoin investment is the best investment, it doesn't mean that you wouldn't look back. There is no investment without risk, so we should always stick with the account that we can afford to lose, because Bitcoin is highly volatile in nature, which you wouldn't be able withstand the pressure if you go above your pocket.
Just have a long-term goal and focus on your investment without panicking about it.
There is risk in any investment or trading. A smart investor prefers long term Bitcoin investment over trading and accumulates Bitcoin regularly with a long term goal. This is not to say that you are out of risk because there is no guarantee that the price will be much higher in 10 years than it is now. Accumulate Bitcoin through discretionary income regardless of the price of Bitcoin. No one can predict the potential price increase or decrease. If you can accumulate Bitcoin regularly every week for 10 years, you will almost certainly have the possibility of making high profits because if you can do regular DCA regardless of the price fluctuations the Bitcoin portfolio will reflect its average purchase price.
The risk are differ, the risk in trading Bitcoin and investing for a long time is different even though the two involves risk, it's true that making profit is not a guarantee for both term and long term Bitcoin investors but the chance of losing your money in trading is high, and if you are not experience enough you will always lose in trading Bitcoin. Long time Bitcoin hasn't lost and i haven't heard that someone lost while investing and holding Bitcoin for long but this doesn't mean there is a guarantee to make profits as long time investor, this is why we are caution to always invest with money we can let go.