1. If BTC stays around 100 USD for a long time, will you purchase it? How much will you purchase?
My experience is that if BTC price stays around the same level for a while, then it's going to fall unless something new occurs that will prompt people to buy.
2. If BTC stays around 100 USD for a long time, and rise to 109 USD suddenly, will you purchase it? How much will you purchase?
I might, especially if I will be anticipating an even bigger increase.
3. If BTC falls bit by bit, will you wait until it reach the certain price in your mind?
Sometimes, other times I will wait until it recovers. It made me sweat a bit though, when the price was <$70 recently.
4. If the BTC price plummets, will you use the whole 3000 USD to purchase BTC without thinking?
I'll usually wait for the price to plummet more before buying cheap.
5. Enjoy your victory and never buy BTC again.
Nah