Thank you guys for just confirming that I am not a maniac hell bent on card destruction. I just play about with the decks - if its a deck I use to perform it'll be one I have replacements of, and usually a cheapish deck anyway. With the decks kept for collection, I have mess about - and then I just reorder them (I am so OCD about deck orders) and put them in the tuck box, in their cabinet. Thank god, I was worried my decks would end up mangled :/ :L
A properly executed spring or faro should do nothing to the deck that ordinary use wouldn't already do. But you never do them properly when you're first learning them - in that case you use something cheap and easily obtained, not something collectible.
And it's spelled "faro". The name comes from a game called Faro, originally known as Pharaoh - Faro was easier to spell. Unlike the common belief that poker was a big deal in the Old West of the late 19th-century U.S., Faro was the game of choice for gambling more often than not, and it was run casino-style at a table in bars all over the place, much like you'd see craps and roulette played today.
One of the features of the game was splitting a shuffled deck in half, flipping over a card from one half and placing bets on whether the next card would be equal to, higher than or lower than the next card. One of the end results was frequently you'd have pairs of even cards ending up together (I think the house won some sort of bonus on two cards of equal value, and many unscrupulous bar owners would fix the game to increase the chances of that happening). When a game was completed, a special shuffle was used (and in some cases, abused) to insure that no two cards from the previous game were still together for the next game - hence, the faro shuffle was born.
The faro is the "perfect" version of the weave shuffle. Whenever you attempt a faro and any two or more cards from the same half remain together, you're not doing a faro, you're doing a weave. Faro shuffles come in two varieties: the in-faro changed the top and bottom cards, while the out-faro kept them the same. Eight consecutive out-faro shuffles will bring a 52-card deck to its original order, as will 52 in-faro shuffles, while 26 in-faro shuffles will reverse the order from the starting order.