Here are some one liners, some of my own, some borrowed when performers have been asked to repeat a trick.

The first time it's magic; the second time is a lesson. I do magic not lessons. (Peter Marucci)

That's an old trick....... here's something new!

Give them a puzzle like the ring and horseshoe and say you'll do another trick if they'll solve it.

It's magic and I can only do it once a day or I'll turn into a pokeman, etc.

The first time is free and the second time is only $10 000 dollars!

A good magician never does the same trick twice and neither do I

If I do it again, you'll probably figure out how it works.... and I think I'll stop while I'm ahead!

If time permits, do it again, but use a different technique.

You could repeat it, but use a different climax.

Some of my props are antiques, and if I do it again, I'm afraid they'll fall apart, not to mention the wear and tear on my hands!

I only do these perplexing miracles once to prevent the audience from going insane!

Do it again? I don't think so, for you know magic is a wonderful institution! But if I do it again, you'll end up in an institution!

I promised Sigfried and Roy I wouldn't do it again, or they wouldn't let me pet their kittens!

If I do it again, I'll sound like an infomercial and you'll just turn me off!

If I do this trick one more time, my fingers will probably fall off my hands!

Grampa always said, "Once is enough if you do it right the first time!"

I went to the Porcelain School of Psychics- that is the school for CRACKPOTS! and crackpots never do a trick twice!

These are a few I've saved over the years. What are a few of your favourite lines?

Darryl the Wizard

Here's one that I've been working with:

"Nope."

Platt,
There's nothing like being simple and direct!
Darryl the Wizard

They are good Darryl!

Very good Daryll and yours Platt, aint too bad either!!

Yeah Platt!

I've tried that and it's particularly effective for 8-year-olds. They then entertain me with their reaction....

:sun:

I think if your act is progressive and structured then the spectator shouldn't want nor get the chance to ask for a repeat performance. Good lines though!

Really? Two of the most-often heard lines at the conclusion of an effect are "How did you do that?" and "Do that again!" I've always been trying to respond to these appropriately and in character. How do you structure your act to avoid these responses?

Cheers!
:sun:

I lead on from my tricks so that by the end of my act they've seen three, maybe four tricks in quick succession. That way, there's no break in between each effect. They can't say "how do you do that?" because that would be asking for the answers to four tricks, so instead they just congratulate me, by which time I'm on my way.

Some excellent lines there. I will have to use some of those.

My stock response is: "At my age, I am happy if I can do it once."

-Marty

Martinkaplan,
I love that line, and at my age I can definitely relate to it!
Darryl the Wizard

I always say "Pardon?". As I'm going deaf anyway, I can use it without guilt! Also, Gene Wilder's "I'm a trifle deaf in this ear - try speaking a little louder next time!", from Charlie and the Chocolate Factory.

Some great lines, guys! I'll add a few to my armory.

With younger kids, sometimes I'll lean real close to them and ask them if they can keep a secret, they of course say yes, expecting me to tell them I say "So can I". This one usually gets a laugh or two.

Sorry, but I rode in here, on a one trick pony. And if I show a trick twice I will have to walk home!

By the time they get done looking out the window for my pony, and figure out that what I said really doesn't make much sense, I am on to the next effect.

BroDavid

Yeah, Charlie and the Chocolate Factory!
Gene Wilder also says "All questions MUST be submitted in writing"...It could be a good line for the "how did you do that?!?" response....

5150,
Bird Brain

I like it Bird Brain, thanks
Joe

My personal favorite,

"Why? What'd I do wrong?"

You're on a need to see basis, and, well, you don't need to see!

I'm on a mission to share my magic with all the people of the world. If you want to see it again you'll have to get in line behind China