Some blogs get ten or more posts per day and others get just one per month.
Both can be successful.
The success of your blog will depend more upon the quality of your content than how frequently you post.
I was thinking that a weekly post would suffice for my blog because the audience isn't one which would be checking frequently + there aren't very many new developments in the industry I'm in that would necessitate more than that.
That sounds like a good reason to post infrequently about newsy items. You don't want to bore people. But... what's wrong with writing some exciting tips and stories about evergreen topics. If you really know your stuff about your industry you should be able to speak about it with enough enthusiasm and expertise that most people will learn and enjoy. If you can't do this then maybe you aren't the right guy for this blog?