How a crash game round works
Each round starts with a multiplier at 1.00x that climbs until it crashes at a random point. You place a bet before the round, then decide when to cash out. If you cash out before the crash your bet pays at the multiplier you reached; if the round crashes first, you lose the bet. Many games let you set an automatic cash-out target so the game cashes out for you, and some allow two bets per round.
The maths: why cashing out later does not change the odds
In the standard design, the chance that a round reaches a given multiplier is roughly the game's RTP divided by that multiplier. At a 97% RTP, about 48.5% of rounds reach 2x, about 19.4% reach 5x and about 9.7% reach 10x. Multiply each chance by its payout and every target returns the same 97% on average. A low target wins often and pays little; a high target rarely wins and pays a lot. Neither is better in the long run, and no timing strategy can change that.
Published RTPs vary by game and operator, and many sit in the high 90s, so check the figure for the specific game you play.
Provably fair crash
Many crash games are provably fair. The operator commits to a chain of results in advance by publishing a hash of a seed, and the crash point of each round is derived from that seed, so it cannot be altered once the round starts. After play you can check the revealed values against the published hash and recompute the crash points yourself. This proves the game was not manipulated while you played, though it says nothing about whether the RTP is favourable - that is a separate figure to check.
Pace, limits and bonuses
Rounds last seconds, so it is easy to place many bets quickly and to lose a lot faster than in slower games. Decide your budget and an auto-cash-out target before you start, and use any available loss or time limits. On bonuses, crash games are frequently excluded from wagering or contribute little, and a maximum bet rule usually applies while a bonus is active, so read the terms before assuming a casino bonus works here.