Elmore Leonard said this about exclamation marks:

You are allowed no more than two or three per 100,000 words of prose.

That worked for him. It should probably work for you as well.

But, as The Atlantic points out, while Leonard kept things pretty tight (only 49 exclamation marks per 100,000 words), other writers let fly and didn’t necessarily suffer for it. James Joyce, for instance, reveled in exclamation marks, averaging about 1 per every 100 words.

So listen to Leonard if you like. But then you’ll never write Finnegans Wake.