Actually anytime that I find something new to write about which is often. I have some google aleets setup to email me new alerts for keywords that I'm interested in. . A good idea is to send yourself pictures and text with ideas for a new blog post to "saved messages" user on Telegram. That way you can access the content betwern phones and computer. You could also use something like evernote for that. It is a good idea to write many posts at a time, some posts takes days of ideas amd thinking and careful piecing together of info sdo dont always expect to finish writing a post in one go from start to finish.