This is a very 'fair' question. It is recommended that 'slabbed' comics be reholdered every seven years. Note the word 'recommended.' I do reholder a lot of my collectibles becuase I like having a 'nice, shiny' holder. I also have a 'touch of OCD.' That being said, keep in mind that CGC only started grading comics about ten years ago. Before that, all these great comics that we love so much were stored without the protection of a plastic slab; and judging by the census, many were taken care of and stood the test of time. As such, I don't think you have to worry about your beloved collection deteriorating any time soon; assuming you use common sense and store the items will proper care.
Kind Regards,
'mint'
(thumbs u