When Pennsylvania Ballet opened its 25th season of performing George Balanchine's full-length Nutcracker Saturday at the Academy of Music, there undoubtedly were people in the audience who were seeing it for the 25th year in a row.

So what's to return for after all this time? Like a favorite holiday movie, repeat viewings only add to the comfort and joy. Even when you know what's coming, you're likely to get chills when it begins to snow onstage. And unlike, say, White Christmas or Love Actually, you'll see different things each time as the casting changes.

Saturday night's performance featured Julie Diana as Sugarplum and Ian Hussey - a replacement for Zachary Hench - as her Cavalier. Diana is a lovely, delicate dancer (though her arms shook uncertainly in the pas de deux), and Hussey, who rose quickly through the ranks and was promoted to principal dancer this fall, was a handsome, confident partner.

Caralin Curcio was a slithery, sultry Coffee, while Jermel Johnson awed with his signature explosive jumps in Tea. Amy Aldridge often performs Dewdrop, and she was perfect for the role, flitting in, out, and among the Flowers.

In the children's roles, Mary Lee Deddens danced and acted nicely as the multilayered Marie, with Juan Rafael Castellanos as her exasperating brother, Fritz. Christian Lavallie had the combined role of Drosselmeier's nephew and the Nutcracker Prince. He was valiant battling the Mouse King and recapping it later in pantomime to Sugarplum.

If you attend year after year, you'll spot rising stars in the program, as young dancers grow into bigger roles. Stephanie Bandura, who is Marie on the Comcast wall, dances the role of a mouse, and Lucas Tischler, an especially impish Fritz a few years ago, now is the Prince in some performances. Many of the Flowers and Snowflakes are company apprentices, Pennsylvania Ballet II dancers, or advanced students at the newly reopened School of Pennsylvania Ballet.

A repeat viewing is also a fine time to take in the low-tech effects, which astonish nonetheless. A few were wonky on opening night, breaking the spell a little: The Nutcracker transferred into the Prince costume a little too slowly. Mother Ginger's immense skirt revealed all the Polichinelles still inside each time one stepped out. And the Angels' costumes are a bit too short, allowing the audience to see their tiny steps rather than letting them appear to float across the stage.

But the magic is still there when the tree - and Marie's whole world - grows before our eyes, when the toy soldiers come to life, when the Philadelphia Boys Choir sings as snow wafts onto the stage when Sugarplum glides across the floor on one pointe, and when Marie and the Prince sail off in a flying walnut boat - even if we can see the wires holding them up. Also charming is the single bunny among the soldiers, perhaps replacing a long-lost piece.

All these small enchantments, supported by Tchaikovsky's gorgeous score, help make Nutcracker one of the rare ballets to appear on many must-see lists year after year. It's easy to see why.