DCA all the way!

I have lost considerable amount of money going all in on trades. I can imagine I could have saved a lot of money DCAing instead pf buying all in.
Learn form my mistakes if you plan to hold long term it is best to have multiple entry points.

as for your second question when BTC reaches 1 mil $ almost every store around the world would be interested in accepting BTC so no need to worry about cashing out. that is at least how I see it.