I don't set an average Bitcoin buying price but I always let the market trend be the reason behind every buying decision I make and what I am waiting for now is the blood bath that always happens after the Bitcoin halving effect.
I really do not have an average number in my portfolio since I prefer to buy and sell almost everyday not just bitcoins but also alternative coins.
You're right, because if you do buy and sell cryptocurrency more especially bitcoin, you will not be able to keep account of the crypto you purchase or sell within some intervals, and more especially if you are a trader that is making profits everyday or anytime you trade also sell whenever you make a profit, because right now i could not remember the last transactions i made within the week because is not written down anywhere, except it's for those that is buying small amount of cryptocurrency can equally know the specifics values of crypto they purchase at a specific time.
I understand that we all have different impressions and desires about our investment but I don't think there's a certain crypto trader who can boldly say she prefers to buy and sell Bitcoin almost every day when the day trader even switch their trading decision to an altcoin at some point.