Are there rules in 5th edition for how books degrade given time/use? The only thing I'm seeing in the covenants book suggests that they do age, but give no mechanics on how.
I seem to remember a system in a previous edition where every time a book was used for a season the reader rolled a die and a botch meant some book damage occurred. If there are no rules like that in 5th edition and you can help me find those older edition rules it would be appreciated especially if they weren't in the core rulebook.
Those rules were* found in WGRE for 4th ed, I don't know if they were in 3rd as well.
They were found among all the very detailed rules for books. Reember that books were rated for 'Physical Quality' as well in these rules, concerned with illumination, coloured inks, clear and readable handwriting, uterine vellum or the negative effects like being cramped, over embellished, poor vellum, poor ink. This stat was adjusted on a pyramid scale where the aforementioned elements gave modifiers of +/-1 to +/-3.
Damage to books was something with a Dex roll, where very poor rolls meant you spilled something, your familiar chewed the book, fires damage, or that one or more gatherings came loose, were smudged or crumpled before being inserted in the wrong place. All these mishaps meant negative points for Physical Quality, and we had some house rules where a competent scribe could repair such things, because IIRC the WGRE did not have rules for this.
It was very detailed back then, and we had much fun with it. Although these days I'd almost prefer the simpe rules from 3rd and 2nd ed ArM.
I suppose the Dex roll would be positively modified for using Lamp ithout Flame rather than candles, and negatively for being taken to the sanctum of a fire or perdo magus, or into a decaying lab
There aren't any rules like this, because they struck me as putting a lot of gamishness into a setting which is meant to be basically realistic. People really don't accidentally damage their books about 10% of the time, and if they did, they'd make second, working copies, and make magic items which stop them being such idiots. Also, it makes your treasures perishable.
"We have plumbed Calebais! We have their Great Book!"
"You had their Great Book but your character spilled wine on it and lowered its Quality."
"I did? That doesn't sound like him. That sounds likes a schmuck."
"You can buy a Virtue that makes you not damage books."
I've just assumed that the two employment seasons a year your covenant librarian spends is tending to the book collection, in the same way the grogs are assumed to tend to their weapons and the tinker is assumed to be fixing/replacing lab tools.
Either way, we don't track weapon quality or lab quality due to degradation over time - so why do it with books? After all, caring for books is an entirely valid professional activity; some people even make a career out of it today!
If the covenant ends up bereft of a librarian, that instead tells me there's book-related stories to be told rather than doing anything statistical.