Ask about on-site facilities' actual opening hours and whether anything's seasonal. A pool that's only open during summer months, or a clubhouse with restricted evening hours outside peak season, changes what a break looks like considerably if you're travelling in spring or autumn.
Start with layers. A coastal breeze can turn a warm afternoon cool within the hour, so pack at least one lightweight waterproof, a jumper or fleece for evenings, and swimwear for the days that do turn properly warm. Even in July and August, an evening walk along the front is usually cooler than you'd expect, so don't leave the extra layer at home on the assumption you won't need it.
Finally, don't assume last-minute means limited facilities. A short break booked at short notice still comes with full access to whatever's on site, whether that's a pool, a clubhouse or coastal walking routes nearby. It simply means less choice over which specific unit you get, which for a quick, spontaneous trip is rarely the deciding factor anyway.
A UK staycation can be planned around almost any budget, provided you know where the genuine savings sit and where cutting corners actually costs you more in the long run.
Timing affects cost as much as accommodation type. Travelling outside school holidays and bank holiday weekends, even by a few days either side, tends to bring costs down considerably, simply because you're avoiding the weeks everyone else is trying to book. If your circumstances allow any flexibility on dates, this is worth more than almost any other single budgeting decision.
For more detail, see
Tingdene holiday lets.
