Time is a risk factor, not a default
Every option dies. Theta is the rent you pay (if long) or collect (if short) for sitting on that clock. Gamma explodes near expiry ATM. Vega is usually larger on longer-dated options. Picking expiry is picking which of those risks you want.
Crypto trades nearly 24/7 with weekend gaps and sudden liquidation cascades. A Friday expiry into a quiet Saturday is a different animal than a Friday expiry into a packed macro calendar.
Map the event to a tenor
If the view is “this print or listing or unlock,” use the expiry that still has time after the event — or that settles just after it, depending on whether you want to hold through or fade the implied move. If you buy the week that expires before the event, you paid for the wrong clock.
The term desk (/t/{asset}/term) plots ATM IV by tenor. A kinked or inverted front often means the market already priced an event. Expected-move math on that tenor is the hurdle your long premium must beat.
Front versus back: practical split
Front-week / monthly: higher gamma, faster theta, more sensitive to a single session. Good for event expression and short-dated hedges you will actively manage. Bad if you cannot watch the book. Back-month: more vega, slower decay, often better for inventory hedges and structural vol views. Worse fill quality on some venues, especially alts.
Calendars and diagonals exist because the term structure itself is a view. If you do not have a term view, do not accidentally create one by mixing random expiries.
Liquidity clusters on listed dates
Major venues concentrate size on quarterly and monthly expiries, then weeklies. “Odd” dates can exist and still be empty. Open interest by expiry on the chain is the simplest filter: if nobody sits there, you will pay to enter and exit.
Settlement time and index differ by venue. Two “Friday” expiries are not the same contract. Check /t/{asset}/sources and venue profiles when you compare books.
Rolling is part of expiry choice
If you know you will roll, start on a liquid tenor so the roll market exists. Rolling is two trades (or a combo): you pay two spreads and two fees. Short-dated options you must roll every week are a lifestyle, not a set-and-forget hedge.
See how-to-roll-options. Size the first expiry as if the roll might fail — because sometimes the next book is a desert.
Practice this on OptionsMatch
Use /t/btc/term, /t/btc/iv-percentile, and /t/btc/chain expiry filters. Calendar research belongs in /t/btc/strategy as a simulated structure, then on a venue combo ticket if you actually trade it.
Educational only. Expiry calendars are venue-specific.