The best thing, according to me would be to sell 30 to 40% of your bitcoin and buy into other top 20 to 30 coins as per the largest market cap and hold on to them for the years to come.
You will be able to diversify and reduce your risks.
That strategy is good because as of right now the bitcoins price is going very high and it is still going up , and the higher it is the less people will be able to get their hands on so their best option is to switch the top altcoin that are close to bitcoin , because they will be easier to mine to get and the exchange rate will go higher the higher the price of bitcoin will.
I think you have to be patient in advance not to panic and rush to sell all of your bitcoin when prices are high, as they may be bitcoin prices will continue to rise and it makes you loss, keep quiet wait until the price stops moving and you can sell all your bitcoin
I guess there will not be any point that bitcoin will stop moving in its price levels. I believe it will keep on moving forward/ fluctuate at least for next 200 years. All the above we never need to sell our bitcoins, we are going to have our local shops accepting bitcoins so we can use bitcoins instead of converting them into fiats.