Stocks and Shares ISA allowance is £20,000 per tax year — and it's use-it-or-lose-it. Most adults use far less. The compound effect of unused allowance over decades is substantial — tax-free growth on £20,000/year of contributions versus taxed alternatives.
How to make it manageable
Auto-contribution from each pay packet. Even £200-300/month adds up. Catch-up contribution from bonus or tax refund to maximise. The full £1,667/month is for higher earners; partial use still valuable.
If you can't maximise, prioritise it over non-tax-advantaged accounts. ISA contributions in your 30s grow tax-free for 30+ years — significantly outperforming equivalent investments in regular accounts.