1. Leaving Everything on an Exchange
An exchange account is convenient right up until it isn't. When an exchange freezes withdrawals, gets hacked, or simply collapses, your coins are only as safe as that company's balance sheet — and history has shown that can mean billions lost in a single implosion, as with FTX. If you're holding for more than a trade or two, moving assets to a wallet you actually control is the difference between owning crypto and owning an IOU. Our wallets and self-custody guide and exchanges guide walk through when to keep funds on-platform and when to move them off.
2. Fat-Fingering an Address
Crypto transactions don't have a "recall" button. Send funds to the wrong address, or the right address on the wrong network, and it's usually gone for good. The cost here isn't hypothetical — it's whatever amount you just typed in before hitting send. Always send a small test amount first, double-check the network matches on both ends, and read our sending transactions guide before moving anything meaningful.
3. Ignoring Taxes Until It's Too Late
In the US, most crypto disposals — selling, swapping, sometimes even spending — are taxable events. Beginners often don't realize this until they've made hundreds of trades across three exchanges and have no idea what they owe. The cost is scrambling every April, or worse, an audit with no records. Tools like Koinly exist specifically to reconstruct your trade history into something a tax preparer can use. Set it up early, not the week before the filing deadline.
4. Buying Tops on FOMO
You see a coin up huge for the week, everyone on social media is suddenly an expert, and you buy in "before it's too late." This is the single most reliable way to buy near a local peak. The pattern repeats every cycle because the emotion — fear of missing out — never changes, even when the coins do. The cost is buying euphoria and selling regret. If you want to understand why prices move the way they do instead of just reacting to them, our technical analysis guide is a better use of your attention than another influencer's chart screenshot.
5. Falling for DM Scams
A stranger slides into your messages, claims to be "support," a "verified trader," or someone who just made a fortune and wants to help you do the same. Every version of this ends with you sending money or your seed phrase to a stranger. No legitimate exchange, project, or wallet provider will ever DM you first asking for your recovery phrase. The cost ranges from a few hundred dollars to entire life savings, and there is no refund department in crypto.
6. Overpaying on Gas Fees
Sending a transaction during a network traffic jam, or approving contracts you don't need, quietly drains money that never shows up as a single dramatic loss — it just leaks out fee by fee. Beginners often don't check network conditions or realize that timing a transaction can save a meaningful percentage of its value. Our gas fees guide explains how fees actually work and how to avoid paying a premium for a transaction that could have waited an hour.
7. Having No Exit Plan
Buying is the easy part. Beginners rarely decide in advance what would make them sell — a price target, a time horizon, a change in the story that got them interested in the first place. Without that plan, decisions get made in the moment, usually during a spike of greed or panic, which is the worst possible time to decide anything. The cost is giving back gains you already had, or holding a loss far longer than you meant to.
Where to Go From Here
None of these mistakes require genius to avoid — they mostly require slowing down and doing a little homework before you act. Start with our full set of guides, which cover the mechanics behind every mistake on this list.
CGH Take: Every mistake on this list is boring to avoid and expensive to make — which is exactly why so many people keep making them.