So i will build my cold stash (trying to increase it with 250%) with my fiat money.
Just remember that holding also requires patience and control. It also requires sufficient resources that you don't have to sell during times of lower prices.
If you're barely getting by and see your holdings worth a fraction of what they were worth, it can be really hard not to sell, especially if you strongly feel the price will keep going down.
Those are the times you should be buying more, albeit incrementally keeping enough spare fiat on hand to buy if it dips further.
Accumulating fiat from your normal income during periods of flat or rising prices is a good policy. That way you're always prepared to buy the dip.
Just never sell.
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It does get easier with time.
In my case, it was excruciating watching the price fall from $266 to $50 after originally buying in at $68 and accumulating well over 100 coins at about $120 per coin.
Thankfully, I had enough sense and intestinal fortitude to hold tight, although I did sell 10 coins for $155 on the "dead" cat bounce by placing a high ask and having it met. I then placed a bid at $97 which was soon met. That was my last "trading". After losing 50 coins to MtGox I realized that all my coins should be offline.
By the time the price had crashed from over $1100 to under $200, it was much easier to take in stride. I went into accumulation mode and was adding coins by the dozen while the price was down.
The recent dive from $1700CAD to barely over $1000CAD at the height of the PBOC panic didn't phase me at all. Now we're back at $1370CAD. and I've managed to add several more coins.
It gets easier all the time. If you start to weaken, just remember the story of one pathetic troll who sold all his coins for $10 each and has been embittered ever since.