Thoughts about event frequencies and "often enough"


I'm having trouble expressing the concept of "not often enough". The most
basic way to say "often" is `よく`, but I think there's a problem in putting
qualifiers on this word. For instance, expressing "more often" with `もっとよく`
would be unnatural and/or wrong.

Here are two examples from [The Jim Breen
dictionary](http://www.csse.monash.edu.au/~jwb/cgi-
bin/wwwjdic.cgi?1Q%C9%D1%C8%CB_1_) for the word [頻]{ひん}[繁]{ぱん} that answer
part of my question. This expresses a "more often" concept:

> メアリーは、もっと頻繁に母親を手伝うと約束した。  
>  Mary promised her mother that she would help her more often.

This is almost to the point of expressing _a degree of frequency_ , but I feel
like it comes up short for what I'm grasping for:

> できるだけ頻繁に辞書を引きなさい。  
>  Refer to the dictionary as often as possible.

How would you say "not often enough"? I'm tempted to try something like
`頻繁さが足りない`, but that has no Google results so it's probably wrong. Would it be
acceptable to use `頻度` instead? Let's say I wanted to say "I don't get updates
often enough" or something like that. What are the best ways to express this
type of thought?

