Complex sentence: Some collectors require more flexibility than a bound stockbook allows and because moving individual stamps from page to page can be time consuming and may cause damage, so several manufacturers produce individual stock pages that can be inserted into loose-leaf folders.
Split into simpler sentences: Some collectors require more flexibility than a bound stockbook allows, as moving individual stamps from page to page can be time consuming and may cause damage. Several manufacturers produce individual stock pages that can be inserted into loose-leaf folders.