I'm new here and a new collector of Tenyo.
Should any discontinued item bought, unused in it's original packaging be kept that way?
Since I would like to use what I buy, should I not buy things in their orig package?

Some items, if you find in original packaging you should keep them that way. I myself, no matter what the item always open it up carefully, and put it back in when I'm done.

If you can buy them with packaging cause if you decide to resell it they seem to go higher if packaging is included!

I'm not a fan of leaving stuff sealed in packages but I like the old Tenyo packaging and have been buying what I can, when I see it. But I MUST open all Tenyo, that's the reason I buy it. If you don't care about resale or don't care about the packaging then toss it.

From personal experiece I find people do pay a premium for old Tenyo in packaging, I have some extras on eBay now. Some are sealed and some are opened.

I've noticed that collectibles like star war toys definitely get a premium price if unopened. I saw The Haunted T-156 on ebay for $150. Would you open that?

I wouldn't pay $150 for that particular trick but yes, I'd open it at any price. I paid pretty good money for a new Floating Lady and I couldn't wait to get my hands on it. The packaging on that is nice so I did keep it intact. Same goes for a few other rare ones I bought recently. Tenyos are almost always worth opening for the great gimmicks.

I do have Vault Vision sealed but only because I have the Magic Works version already. In that case I did buy it because I thought it would be cool to have the original packaging for one of my favorite Tenyos.

I always open the package and put the trick in my 'Tenyo-display cabinet', however the past year I do it very carefully and keep the packaging since tricks sell for more when the original packaging is there. I'm not planning to sell my tricks in a 100 years however but you never know ... .
My experience is that a trick 'mint-unopened' sells for about the same as one that is 'opened, looked at and put back in package'.
I consider myself a very vidid Tenyo collector (I have about 180 original Tenyo items and one day I hope to have them all although that won't happen I'm afraid ...) and actually don't care if a rare item that I'm missing hasn't got the original packaging; even a copy of the instructions is fine by me, as long as the trick is in 'like-new' condition

I noticed that you all are new users.
Killertweety said he/she has got 180 tricks ( wow!) I've got about 20, but I just started not too long ago.
how about the rest of you.
how many have you got and how long have you been collecting.