Yes, those who are waiting for the bitcoin price and then they can buy, would never buy because on every drop they become more fearful and think that it may drop more. If anyone hasn't had any positions in Bitcoin, I think they should buy with 25% of the portfolio now and then buy more on every dip. This is because in case the price pumps from here and doesn't give a pullback, the person won't be left waiting. Also, I would not feel nervous buying near 110K because I know that this is not the ultimate top for this cycle and for years to come, it is like buying under 50K 
I wouldn't wait I would just buy and hold. Because why would I wait? We don't know if it's top or not. Even if it is top we will see higher in the future. So just dip in and buy whatever you can.
Hold as long as you don't need to withdraw and buy more as long as you have spare money to invest. There is no other option. Buy buy and buy more until you have decent amount. Then you can wait and enjoy higher prices with as much as Bitcoin you have in your hand.