When to sell when you don’t hold a large stake?

I don't have a lot of money invested in stocks. About $9k total and its split up in a couple different stocks at about $1.5k each.

I am currently up on quite a few of them, but I don't know when to sell. I have this feeling in my gut to just hold on to them basically forever but I also know that at some point I do need to sell them and reinvest somewhere else.

For example, I have 3.5 stocks in Microsoft at a price point of $301. Now the stock is at $430 so I have made a decent profit.

I won't be making huge gains on only 3.5 stocks of a company so should I just be dipping out and reinvesting elsewhere or should I hold on to these bad bois for as long as I can?