Travel credit cards can be quite lucrative — from earning deeply discounted first-class flights to receiving complimentary hotel elite status, the perks these cards offer can significantly improve your travel life.

But it’s not all high-end award redemptions and free checked baggage; every travel credit card comes with its own set of points, redemption values, rules and fine print. Understanding these is key, but even the most experienced among us get it wrong sometimes. Whether you’re a travel card veteran or a total newbie, let’s take a look at the 10 worst travel credit card mistakes.

1. Spending too much

Many different travel credit cards come with a welcome offer, which usually means you’ll get a lump sum of bonus points after meeting a certain spending threshold. While this can be a good way to earn a lot of points at once, not having a plan for how to meet that spending requirement can be a big mistake.

Buying things just to meet your spending goal can land you in trouble, as can having additional expenses that weren’t already in your budget. Before you sign up for a card — and even after — make sure that your purchases make sense. It’s never a good idea to buy something you can’t afford, even if it helps you meet the welcome offer requirements. If you aren’t careful, pricey interest rates on travel credit cards can end up costing you more than you’ll gain.

2. Not spending enough

While it’s important to be smart with your spending and expenses, it’s also important to remember to spend enough. Travel credit card welcome offers usually come with a time limit — for example, with the Capital One Venture Rewards Credit Card: Enjoy a one-time bonus of 75,000 miles once you spend $4,000 on purchases within 3 months from account opening, equal to $750 in travel.

Failing to meet the spending requirement within the set time frame would disqualify you from earning the bonus, which can be a big hit to your award travel dreams.