How important is an opening sequence or a closing sequence?

[JayZippo]

Some of my favorite toobers do not have any opening or closing to their videos. They have millions of subs.

But how important do you think that is to any video or to any channel for that matter?

I have a client now and he is obsessiong about how many lines the title should be in the opening. He hired me for 25 videos, and they are simple. An opening, him trying to be some guru and the closing.

I am trying to tell him it really doesn't matter if the title is two lines or one like:

Looks like this:

Week#10

The difference between pain, anger & depression

(he wants that all on one line and it wont fit)

So I have it

Week#10

The difference between
pain, anger & depression

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Sounds so trivial but he seems to think its make or break...

So in light of that... how important are they?

[Rhody Seth]

I don't think an opening matters much at all and everything I've heard is that if you must have an opening keep it really short.

I tend to agree.  I don't use an opening per se though sometimes I'll start with a few quick choice shots before starting at the beginning of whatever my trip is. 

A closing is probably more effective because by that point if the viewer stuck around they are more likely to be engaged by the closing I would think.