I sold December 2028 $520 puts on Berkshire in January. They are about 16% cheaper now, but haven't been exercised. The price looks quite good on those. Are they too long for your purposes?

That's a little longer than I normally go, even Jan 2028 is on the long side for me, but it's probably a good deal. It seems likely that the stock price will be well above $520 by then, so it's "free money", probably. The only thing is that you do have to have the ability to let it be exercised, which is a commitment, and at some point the maximum possible rate of return remaining won't be interesting at all. You'll probably want to buy them back when half or 2/3 of the time has elapsed but you've already earned 80-90% of the profit. You can always write higher strike ones then if you want, to keep it interesting.

If you want to keep an eye on the likelihood of exercise, first off look at the stock price...nobody will exercise something that is out of the money because they would be selling stock below the current price. So as soon as the price is above $520 it won't happen. Then look at the bid price from time to time. If your counterparty wants to realize some profit, they'll almost always look at whether they'd get more money by exercising the option and selling the stock, or by selling the option. So long as the bid (not ask, not last) shows some time value on the table, exercise is very unlikely. The only time I've seen that is during a sharp market selloff, when presumably the counterparty thinks the dip won't last and wants to pull the trigger right away.

Jim