When asked to name the greatest invention in human history, Albert Einstein is rumored to have replied "compound interest."
Whether Einstein actually said that or not, the fact is that many smart people take advantage of it. It has been said that if you understand it then you will receive it, and if you don't then you will pay it (usually in the form of credit card debt).
Compound interest occurs when the interest is added to the principal so that from that moment forward the interest itself also earns interest.
In the context of covered call investing, the "interest" is the option premium you receive and the "compounding" is the fact that you reinvest your gains each month.
So, if you are patient and disciplined, you could 4x your investment in 11.7 years if you can get 1%/month. That may seem like a long time but slow and steady wins the race.
Now, in the real world no one is going to achieve 1%/month for 140 straight months. Some months you'll do better and some months you'll do worse. But if you target slightly higher than 1%/month, say 1.3% or 1.5%/month, then the months you exceed 1% should make up for the months you come in below that.
The most conservative way is to sell short-term deep in the money calls. If you don't want to take single-stock risk then do it with ETFs.
One of Born To Sell's tools is called "Max Protection" which is a covered call filter where you enter your desired Annualized Return If Flat (12%, for example, if you are targeting 1%/month) and then it shows you all matching covered calls and sorts them by Downside Protection. If you have a 'return goal' then this is quite the time saver to help you identify possible trades.
Each of those ETFs would have to fall by the amount of downside protection listed before you would lose money. And if they stay above their deep-in-the-money-strike prices by Oct 22nd then you will make a minimum of 1%/month. Note that many of them have already come down quite a bit in the last couple of months. While they could fall an additional 16% (or more) in the next 30 days, it seems like a reasonable risk to take (and 1%/month beats the interest you'll get on cash or bonds right now).