At what point do you cut your losses?

I’m new to investing. Been doing it about two months and overall have better returns than just leaving the money in a high yield savings account.

One of the first trades I did was buying TSLA at about 170. It ended up dropping to 165 or so and I sold to prevent losses. It dropped to the 140s but obviously now it is in the 180s. I accepted a loss when holding for not even that much longer would have made decent profit.

After I learned a lesson about patience there, I’ve been trying to hold, but a few choices I’ve made don’t show signs of rebounding (SEDG is down 20% today and has been decreasing pretty steadily since I bought in).

I’m still undecided if I’d like to cut my losses and try to invest in something that will give more returns in the meantime, or if I hope that the solar sector has a strong rebound in the (very) long term and just continue to hold.

In your experience, when do you cut your losses? Do you have any examples of sells that saved you money, or sells that you regret?