Optimal Bet Size for a Long Session: A Simple Bankroll & Risk of Ruin Approach

Long casino sessions are rarely lost because of one “bad beat”. More often, the problem is an oversized stake that turns normal variance into a bankroll-ending swing. If your goal is to play for longer, keep control, and avoid going broke, you need a stake size that matches your bankroll and the volatility of the game. This guide explains a practical method used by disciplined players: define your bankroll, choose a sensible unit size, and check your risk of ruin before you start. Everything is written for real-world play in 2026, with clear steps and examples you can actually apply.

Start with a session bankroll and define your “unit”

The first step is to separate your gambling money from everything else. A bankroll for a session (or for a week/month) should be an amount you can afford to lose without affecting bills, savings, or obligations. Once you have that number, you stop thinking in “£5 bets” or “£20 spins” and start thinking in units.

A unit is simply a fraction of your bankroll. For long sessions, most experienced players keep their base unit small so that normal downswings don’t end the session early. A common, practical range is 0.5% to 2% of your session bankroll for low-to-medium volatility games, and even lower for high volatility slots.

Example: if your session bankroll is £500, then 1 unit at 1% is £5. If you choose 0.5% per unit, 1 unit becomes £2.50. The smaller unit usually feels “slow”, but it buys you time, more decisions, and more chances for the statistical edge (or luck) to work without wiping you out.

How to choose a unit size that actually supports a long session

A good unit size is one that lets you survive routine variance. For many table games, a unit around 1% of bankroll is a sensible starting point. For higher-volatility games (especially many modern slots), 0.2%–0.5% is often more realistic if you want to avoid fast bust-outs.

Think in “how many units can I lose before the session is over?” If your bankroll is only 50 units, a normal downswing can end your play quickly. If your bankroll is 200 units, the same downswing is uncomfortable but survivable. That is why long-session planning usually pushes the unit size down, not up.

As a simple rule: aim for at least 100 units for table games and at least 200 units for high-volatility slots if your priority is session length. That doesn’t guarantee success, but it reduces the chance that ordinary swings end your session before you’ve even had time to settle into your strategy.

Understand risk of ruin in plain terms (and why it changes by game)

Risk of ruin is the probability that your bankroll hits zero (or your stop-loss) before you hit your target or decide to end. You don’t need a maths degree to use the idea: the bigger your stake relative to your bankroll, the higher your chance of going broke during normal variance.

What many people miss is that risk of ruin isn’t the same across games. A low house edge game with gentle variance (for example, some blackjack styles played with proper discipline) behaves differently from a high-volatility slot that can swing hard for long stretches. Two players can have the same bankroll and the same “£ per bet”, yet completely different survival chances.

In 2026, many casinos promote fast, volatile games that feel exciting but punish oversized stakes quickly. If you want longer sessions, your plan must match volatility: the more violent the swings, the smaller your base unit should be.

A simple “ruin check” you can do before playing

Here is a practical check: estimate how many bets (or spins/hands) you’ll play, then compare that to your number of units. If you plan to play 600 spins on a slot and your bankroll only covers 100 spins at your chosen stake, you’re depending on immediate luck just to stay seated.

For table games, you can think in terms of “expected losing streaks”. Even with perfect play, you can easily have 10–20 losing decisions in a row over a long session. If that streak costs you 20%–40% of your bankroll, your unit size is probably too aggressive for the time you want to play.

For slots, the check is stricter. High-volatility slots can deliver long stretches without meaningful wins. If your bankroll can’t survive a long “dry” period, you’ll often bust before any big hit arrives. That’s why a smaller unit is not timid — it’s a tool for staying in the game long enough for variance to unfold naturally.

Build a long-session staking plan: base bet, limits, and adjustments

Once you have a unit size, build a simple plan with three parts: your base bet, your stop-loss, and your stop-win. The base bet is usually 1 unit (or less for slots). The stop-loss is a point where you end the session to prevent emotional chasing. The stop-win is optional but helpful, especially if you know you tend to give profits back.

For long sessions, many disciplined players avoid increasing stake after losses. Progressive systems often look clever but usually raise risk of ruin quickly. A stable unit approach keeps your risk consistent and makes it easier to control emotions during downswings.

If you want adjustments, keep them structured. For example, you might increase from 1 unit to 1.25 units only after you’re up by a set number of units, and you revert to 1 unit if you drop back. The key is that changes are rule-based, not emotion-based.

Worked examples for common bankrolls (table games and slots)

Example A (table game): bankroll £300, aiming for a long session. Choose 1% unit = £3. That gives you 100 units. A rough losing run of 20 units costs £60, which is noticeable but not fatal. You can still play calmly and stick to decisions rather than chasing.

Example B (slot session): bankroll £300 on a high-volatility slot. Choose 0.25% unit = £0.75 per spin. That gives you 400 units, which is far more realistic for long play. If you stake £3 per spin instead, you have only 100 units and may bust quickly during a normal cold stretch.

Example C (mixed session): bankroll £1,000 with both tables and slots. Use separate unit sizes: 1% (£10) for tables and 0.2% (£2) for high-volatility slots. The mistake many players make is using the same unit everywhere, which quietly increases ruin risk when they switch to a more volatile game.