Fitting a cat flap is not difficult, exactly. It's a hole saw, a bit of measuring, and an afternoon. It is also irreversible, draughty if you get it slightly wrong, and completely unnecessary if somebody is already opening the door for you whenever you ask.

I wrote early in this series that Lightning is the flap. This article is about cutting your own — running a Lightning node yourself instead of using a wallet that handles it for you — and the honest answer for most readers is going to be no, and here's what to do instead.

1. What a Node Actually Does

Running a Lightning node means your machine holds the channels. You decide who to connect to, how much capital sits in each channel, and when to open and close them. Nobody manages liquidity on your behalf and nobody can freeze you.

It also means your money is in software you are responsible for keeping online, updated and backed up correctly. That's the trade, stated plainly, and everything below follows from it.

2. The Three Honest Reasons to Run One

Only three good ones, in my view:

• You want to receive at scale without a third party. A business taking Lightning payments all day, or a creator with meaningful donation volume, eventually outgrows a custodial wallet. Your own node plus BTCPay is the clean answer.
• You want to route, as a project. Earning routing fees is a hobby with a small, real yield and a lot of learning attached. Treat it as a learning exercise that occasionally pays for itself, not an investment.
• You want to verify and self-host on principle. You already run a Bitcoin node, your wallet already points at it, and the Lightning node is the next thing you want under your own roof. Perfectly good reason, and the one I'd expect from most people who've read this far.

Notice what isn't on that list: spending. If you mainly want to pay for things with Lightning, a modern self-custodial mobile wallet already gives you keys, channels and liquidity management without any of the operational burden. For that use, cutting your own flap buys you almost nothing.

3. What It Actually Costs You

Not money — the hardware is cheap and may already be on your desk. The costs are elsewhere:

• Liquidity is capital with a job. Coins locked in channels aren't in cold storage and aren't earning anything by sitting there. Opening and closing channels are on-chain transactions, so a badly planned channel layout costs real fees to fix.
• Inbound liquidity is the beginner's wall. Opening a channel gives you the ability to send. Receiving requires capacity on the other side, which you must acquire — by buying it from a liquidity provider, by earning it through spending, or by partnering with a well-connected node. Every new node operator hits this and most are surprised by it.
• Uptime matters. A routing node that's offline is useless and can be penalised by its peers closing channels. A spending node that's offline just can't pay, which is more forgivable.
• Backups work differently. Your seed phrase alone may not be enough. Lightning requires channel state backups — static channel backups at minimum — and restoring badly can mean losing funds in channels. This is the single most common way people lose money running a node, and it isn't the dramatic way: it's a routine restore done without the right file.

4. If You Do It Anyway

The sane path, in order:

• Start with a Bitcoin node you already run and trust. Lightning on top of someone else's chain data defeats half the point.
• Use a managed distribution — Umbrel, Start9, RaspiBlitz and similar wrap the setup, updates and backups in something maintainable. Writing your own stack from source is a different hobby.
• Fund it with an amount you can afford to lose. Not a savings balance. An amount sized like tuition, because for the first six months that's what it is.
• Open few, well-chosen channels rather than many small ones. Fewer, larger channels route better and cost less to maintain.
• Set up channel backups before funding anything, and test a restore on a throwaway setup first. Same drill as the hardware wallet, same reason.
• Keep savings somewhere else entirely. The node holds working capital. The cold storage you wrote a letter about is a different wallet and never touches this.

5. The Honest Verdict

If you want Lightning for payments: use a good self-custodial mobile wallet. You hold the keys, the hard parts are handled, and you lose almost nothing that matters.

If you're receiving at volume, or you genuinely want to run infrastructure: do it, with a managed distribution, with capital you treat as expendable, with backups tested before the money arrives.

And if you're unsure which of those you are, you're the first one. That's not a criticism — it's most people, including most people who are quite serious about bitcoin.