This time: 'limits, Good Omens.'
There are limits to that sort of thing.
Aziraphale overhears humans discussing them all the time - not on purpose, of course, he doesn’t eavesdrop, but sometimes he just can’t help overhearing. Humans talk about their alcohol limits, their pain limits, their low willingness to put up with other humans’ stupidity (a complaint he quite understands, on some levels), even their... er... romantic limits, in a few cases.
Those are usually people who overstepped their personal alcohol tolerance quite some time ago.
In any case, he attempts to abide by such standards as best he can, at least in public. He really has no set alcohol tolerance - aside from it varying a bit from body to body, he can sober himself up whenever necessary - and... well. The matter of romantic limits doesn’t really apply, under the circumstances. Perhaps if one of them really were human - but that’s another story altogether.
He has to consider the matter carefully, in this case. It would be a rather obvious flouting of any number of bylaws and expectations of the world, should a human ever come to notice it. But given the trouble he goes to to avoid humans in the first place, particularly the sort who arrive with a purchase in mind, perhaps it wouldn’t present such a problem. And if his superiors were ever to notice, he suspects he can claim preserving knowledge for the good of all.
And so Aziraphale sighs, and makes his bookshop bigger on the inside than it is from without. He can’t bear keeping half his books in various storage units all over Europe anymore (he’ll be lucky if some of them haven’t been damaged by time, but that’s nothing he can’t fix), and the building was bursting at the seams anyway.
He’ll set the building to rights, if he ever sees the need to relocate.