[Pre-release review written before the last three scenarios of The Forgotten Age were published.]
Okay, this is a weird one. Unlike Ace in the Hole which, for the same XP cost, is instantly and reliably useful, Borrowed Time can only really be useful if you build your entire deck around it.
While superficially similar to Ace, Borrowed Time gives you deferred actions rather than extra ones. Why would this be useful? Mainly because of the combos you can achieve with cards that confer bonuses until the end of the round, the phase, or the investigator's turn. That means building a deck with one-round-boost assets, or at least a large number of events and skills.
Ideally, the one-round boosts should come from reusable assets, because then you could reliably spend alternate turns saving up actions and then taking pumped-up super-turns. At the time of writing, the assets with one-round boosts (based on the search strings 'x:"end of the"' and 'x:"end of your"' on ArkhamDB) are:
- Keen Eye, which only works for a character who can buy 3XP Rogue and Guardian cards (and is a pretty underwhelming combo anyway);
- Encyclopedia, which only works for a character who can buy 2XP Seeker and 3XP Rogue cards; and
- The Red-Gloved Man, which doesn't actually stay in play for more than a round, so it's more like an event for our purposes.
So, basically, Lola Hayes with Encyclopedia is your only option at the moment, but it's a pretty compelling option. More on that in a moment.
Turning to single-use cards, first of all you should obviously try to run two copies of Pay Day with Borrowed Time. For 0XP cards, Intrepid, Sleight of Hand, and especially Fight or Flight should usually be included in a Borrowed Time deck where feasible. Mind over Matter won't play well with any of the characters so far who can actually buy Borrowed Time, but who knows what the future holds?
Under the current card-mix, the best-case non-Lola scenario seems to be recurring The Red-Gloved Man - take a Rogue who can buy Survivor cards like Jenny Barnes or Finn Edwards, and use A Chance Encounter to replay The Red-Gloved Man, and then use Resourceful to replay A Chance Encounter. That's powerful if it works, but it hardly ever will - you'd basically be building your deck in the hope that you draw Borrowed Time and The Red-Gloved Man early enough to put them to work, which is unlikely even if you doubled up on The Red-Gloved Man for a total of 16XP. It seems pretty clear that Jenny and Finn have better builds available at that level.
Having said all that, I think a Borrowed Time/Encyclopedia combo has some real potential for Lola or for a hypothetical future Rogue/Seeker character. The Seeker class has Research Librarian and No Stone Unturned to improve the chances that the Investigator can actually get Encyclopedia and Borrowed Time into play. Maybe supplement with Quick Thinking, upgraded .41 Derringer, or the normally-inefficient Leo De Luca in order to get even more boosted actions. In Lola's case, she also has access to all those lovely Survivor cards, so a Lola/Borrowed Time deck could be a serious powerhouse.
For anybody else, though, this seems like a pretty dubious thing to throw 6XP at.