The other answers totally overrate the work necessary to keep your Legacy game reusable. I spent the most time of that process on writing these instructions!
We played Legacy reversible without killing the fun or investing a lot of time. Some of it actually improved the fluency of the game play.
What we additionally used (you can do with less)
- 3 sealable transparent plastic bags
- color photocopier (having one close by is probably the biggest challenge)
- Post-It notes (often only the sticky part)
- scissors
- paper glue stick
How we did it
General
Put things aside, instead of destroying them.
Dossier doors
Some doors had associated text in the door retainer with no clue as to which door number that text was coming from. We turned (e.g.) “open box 3” on the retainer into “X → open box 3” with a pen to remember that “X” was the cause which revealed that prompt.
Start of the campaign
Reversible or not: use one bag to keep the game end bonus material (e.g. skills), the other to keep the in-game-material (e.g. scars). This way nothing mixes with the rest.
Once we had two surprise-boxes empty, we used the space they left in the game box to bury copied and “destroyed” material for eventual retrieval.
We photocopied the front side of the character cards and the last page of the manual. These are the only things you need to write on. The character card back sides have a simple table which we drew by hand (a header and a single line).
We also photocopied the sticker sheet (minus the small stickers, see next paragraph).
Small stickers
We actually used the original small, repeating sticker and stuck them on the board (e.g. panic levels, permanent research facilities, destroyed permanent research facilities). But we never stuck stickers over existing ones: if we had to, we peeled the stickers off, put them back on the sticker sheet and reused them. Some repeating stickers were not limited (e.g. panic level), but some were (e.g. permanent research facilities). It was very easy to keep count of what resources we still officially had and which were only in stock because of sticker removal. For example, if you never lose a permanent research facilities in the first place, or never created six in total, you will never need to remember that six is the maximum. – Otherwise, well, keep that in mind.
After the campaign it was a little tedious to peel so many panic level stickers off, but totally doable. We also put them back on some blank scrap plastic sheet instead of the original sticker sheet for practical and preserving reasons.
Those stickers might eventually wear out, but I don’t plan to play the campaign myself again, and my friends should have enough energy and do-it-yourself-skills to create and use makeshift post-it variants of them: a little yellow square with a “2” on it or a little white sticker in the shape of a house – nothing complicated.
Bigger board stickers
There are only very few. So we either used a Post-It and copied the text/picture by hand, or we made a photocopy, glued it on a Post-It to create a sticky copy. In “Season 2” we started using adhesive spray to turn a photocopy into a Post-It.
Stickers which go on cards
Those usually had a headline and some explanatory text. We used Post-Its and wrote only the headline on them. We kept the originals as reference. And we actually also made photocopies: their only purpose was to indicate that we still had that sticker in stock. We discarded the paper copy once the corresponding Post-It was on a card.
Rule book stickers
We used those as intended with one addition: we marked the sticker (actually the space next to it) with the letter the sticker had. E.g. a little “G” marked the space for sticker “G”. This served only as reference for the final cover-up with Post-Its and can also be done later (with the help of the PDF rule book).
Surprise boxes
Open them from the side for better reuse. – They are easy to reconstruct with this list on boardgamesgeek. You can also drop a note inside (a single word was enough for us) to undo their opening without the help of the Internet.
Pawn actions
The rule book discoveries are kept in sync with stickers for 4 action reference cards. We created only one self-made paper reference sheet with photocopied stickers. That was easy, fun and really enough.
Final notes
As the cards have labels, it was very simple to re-create the legacy deck. We put a Post-It over scratch fields on them. We also created a secondary legacy deck consisting of the pristine dossier doors left:
- it was easy to order those doors chronologically by reading the legacy deck again (only door 30 had no fixed order)
- a considerable part of the doors could be moved to the surprise boxes as those were discovered at the same time
- it turned out that almost all doors left over had a nice size to be stacked up to form a deck
- it made perfect sense to put the two annoying tiny doors (hard to stack with the bigger ones) on top of the secondary legacy deck
- door 19 was the first to open anyway
- door 30 had no fixed order and was “in your face” this way (but not too much)
- the empty dossier door retainers are pretty much useless, except for the “X leads to the opening of box 9”, which we wrote directly on the Post-Its covering the additions in the rule book
- the third sealable transparent bag helped to hold the secondary legacy deck together, even with copied papers in it (so the next players don’t need a photocopier any more)
Have fun!