in a website, can we change meta description in monthly basis? is it good activity for static website?
I don't think so. You should have your page what it is about, have a title and description for it, then keep it that way unless the relevance or purpose of that page has changed. Google likes websites that have updated information. If you want to make changes, maybe add or edit some parts of the page, but keep the meta info consistent. Aurelius
I would advise you not to change your meta description on a monthly basis. This will be bad for your rankings and you may lose your SERPs on your pages that are ranking well.
I would inform you not to change your meta account from month to month. This is bad for your search rankings and you will eliminate your Search page results on your own webpages which might be standing well.
No changing meta desc frequently is just not good for a static website and if you still want to do that switch to a dynamic website. I would also stress on the point that, changing meta desc is not a good activity, Because it gets time to get indexed and changing it frequently means you are not going to extract that much traffic from the search engines.
Pick the best meta title, description and keywords for your website and don't change it. Unless of course there is a typo or you're doing a major keyword switch, but remember, when you change it, search engines may deduct rankings.