One of the best constraints of the TV show is the limited budget (along with the lack of mobile phone). It's frequently the case that teams panic spend in order stay ahead, but are hurt by those decisions later in the race.

Over the series people have also developed strategies within those constraints - so it's quite frequent to see teams earning money in the penultimate leg and taking the time hit in order to splash out in the final leg.

It's a great show if you're able to get hold of it.