Sure, bargain hunters have traditionally waited for those last-minute deals.

But in some cases, waiting too long to book is a risky move.

Here’s when it makes sense to book ahead of time.

In some special-access experiences, only a limited number of travelers are allowed, which means that slots can fill up fast.

We’re talking places like Machu Picchu, where the limit on tourists is 2,500 a day. If you’re planning to travel in the high season, expect to book as much as six months ahead of time.

Early planning makes sense if your dates are inflexible, like families who have to work around school schedules.

If you wait too long, you’re likely to get locked out of your dream vacation.

But like I always say, don’t let school get in the way of education.

If you can avoid traveling when everyone else is, you’re looking at much better deals. And then there the times when it does pay to plan ahead.

Some tour companies like Trafalgar and river cruises like Uniworld will often reward early bookers with discounts and perks.

But that may mean paying in full early on, which means you’re officially locked into those plans.

For more tips, visit our Budget Travel section.

And check out the rest of our Daily Travel Tips here.