I don't tend to read my own blog that often, which means I don't spend much time looking at it. So it wasn't until I started investigating how to disable Blogger's forced lightbox viewer that I spotted I had a problem with the followers gadget on some of my blogs. Developing my original fix to that problem involved reloading my blog over and over again as I tried different things. Sometimes the followers gadget appeared and sometimes it didn't. There didn't seem to be any pattern but there was definitely a problem.
Strangely it wasn't a script associated directly with the followers gadget that solved the problem, but rather a script for the +1 button. This did, however, explain why I was only seeing the problem on my blogs which included the sharing buttons below each post. So if you find that your followers gadget sometimes doesn't appear then it might be worth trying the following fix.
<head>insert the following:
This fixed the problem for me, and I've suggested the fix in a couple of threads on the Blogger forum and it seems to have worked there as well, so hopefully it should stop your followers gadget disappearing for good!