I always pack a pair of compact slip on shoes of some sort, they weigh little, squash down - or if not you can pack something inside them if your one of those who tours on a compeltely unsuitable bike with nothing more than a tank bag.
Talking of packing, short trip coming up and the what Luggage dilema strikes, with the Mrs it is easy, she has one pannier for Hotel stuff (clothes etc), I have the other one and our top boxes are for whatever other crap we need (spare gloves etc)
Short solo trips and the options expand:
Roll Bag:
Pros: Light, compact, allows for easy filtering, holds plenty for a week or so.
Cons: Requires strapping on / taking off each day, never 100% certain it is gonna be there at the next stop, if it pisses down you end up with a bag with a days road shite all over it to take into Hotel room, if you need to get something it is a PITA - much worse if your trying to find your waterproof gloves in the pissing rain, and in the process you flood all of your stuff.
All the Boxes
Pros: Loads of room, inner bag for Hotel stuff in one, rooms for tools / puncture kits / spare gloves / waterproofs / provisions in 2nd pannier, empty top box to stow lid / nav / gloves etc when stopping.
Cons: You have added 20KG to the bike before you pack anything, you will massively over-pack, filtering more difficult (or impossible if you have 2 45L metal panniers out in the breeze - and noticeable increase in fuel consumption. On "non Transit" days you either need to drag panniers into the room or spend the day dragging all these empty metal boxes around.
Just the Panniers
Pro's: Nobody loves a top box, hideous things, placed in the worst possible place for handling and aeordynamics. Pannier have more than enough room, in theory handling improved and some fuel saved, you will certainly out-corner & outrun all your bikes mates now.
Cons: You will get pissed of carrying your lid everywhere, On "non Transit" days you either need to drag panniers into the room or spend the day dragging thema round - if you remove them you now have nowhere for your spare gloves and the puncture kit you would only ever need when not carrying it. You will still over-pack.
In my small pannier I can carry tookit, spare visor, waterproofs (extra waterproofing as my textiles are waterproof, but in biblical rain it helps having an oversuit to reduce how much finds its way through the gaps) inner liners (in case it gets cold) puncture kit, gaffa tape, cable ties, visor cleaning kit, bottle of water, half a dozen pais of gloves - and still have room to stash sat-nav when stopping. With a roll bag 75% of this shit would be left at home.
I often end up with 3 boxes to cover all eventualites and convenience, with one full pannier, one half empty pannier and an empty top box.
1st world problem for sure!