Facts --- A [**P2WPKH** input weighs](https://bitcoin.stackexchange.com/q/100159/5406) 68 vB (assuming the worst-case with a high-r signature, -0.25 vB with a low-r signature) and a P2WPKH output weighs 31 vB for a total of 99 vB. A [**P2TR** input weighs](https://bitcoin.stackexchange.com/q/111395/5406) 57.5 vB and the output weighs 43 vB for a total of 101.5 vB. P2WPKH is cheaper when you pay yourself as often as you spend inputs --- P2TR is about 1.5% more expensive across the lifecycle! Does that mean that I should continue using P2WPKH? Yes, _if_ almost all of your transactions have a single input and create change, you could indeed save a tiny portion of fees by using P2WPKH. The below table shows the total weight of transactions under the assumption that most of them are single-input and creating change, created using either P2TR or P2WPKH outputs, and one of X transactions having a two inputs instead of one: [![Table that compares total weights for ][1]][1] If only one out of seven transactions uses two inputs and you always create change, you’ll be able to save up to 1.5% by sticking to P2WPKH. If 1 out of 6 transactions has at least two inputs or if you can sometimes avoid creating change, your total transaction weight would end up being lower if you use P2TR. Most of the time, other users are paying you, and usually the sender pays for the output (or you pay a flat fee to withdraw regardless of output type). Whenever others pay you, you _only_ pay for the input. P2TR inputs are 15% cheaper than P2WPKH inputs (57.5 vB vs 68 vB). Yes, that externalizes the cost to the sender, but the senders don’t get a say in how the recipient wants to get paid, and they generally already are good to pay to P2WSH (which costs the same as P2TR). Batching ---- Whenever you use more inputs than you send outputs to yourself (e.g. when you make big transactions for batching payments, consolidation transactions, the payments you receive are smaller than the ones you make), or you’re able to avoid change altogether, it will be cheaper to use P2TR: [![enter image description here][2]][2] User scenarios ---- Hardly any wallet operator’s spending pattern would ever match the assumption that most transactions have only one input and create change. Let’s consider a few user scenarios. **Merchant/Service** If you offer a service or are a merchant, you will receive many smallish payments or deposits, and occasionally will make larger payments to cover costs or pay suppliers. Whenever you get paid, your customers will pay for your recipient output, but you only pay for the inputs. When you make your larger payments, you are likely to have two or more inputs. P2TR inputs are 15% cheaper than P2WPKH inputs (57.5 vB vs 68 vB). You may occasionally consolidate many low-value UTXOs at opportune mempool condions. Generally, your count of inputs will heavily outweigh your count of change outputs. It follows that it’s cheaper for you to use P2TR. **Hodler** If you regularly DCA, you will have many small-value UTXOs. You may occasionally sweep them into cold storage. Then, or whenever else that you do create a transaction, it will likely have multiple inputs. If you buy bigger amounts at once, you may still hold your UTXOs for an unknown amount of time, and it is impossible to predict what the feerates will be like when you actually want to spend the UTXOs. In either case, you will create few change outputs, and it benefits you to have smaller inputs whenever you do decide to spend. **Pay as often as you receive** It’s not clear who would have such a spending pattern, but let’s say you receive payments as often as you make them and every payment creates change. In that case, only half of the UTXOs you own were sent to you by yourself. Clearly, in the long-term you have to spend about twice as many inputs as you create change outputs. **Multi-wallet setup with spend-only wallet** One exception would be, if you operate a “spend-only wallet” that you occasionally top up with a few large UTXOs from which you peel off payments. In that case, I could see how you might actually end up with creating change 7× as often as the number of times that you have a second input. In that case, you’d be able to _save up to 1.5%_ by using P2WPKH instead of P2TR for the spend-only wallet. **Exchange/Brokerage** If you give out P2TR deposit addresses, your customers pay for the larger outputs, and you have less cost when you spend those deposits. Most exchanges and brokerages batch withdrawals, and such transactions will often have multiple inputs, but only require a single change output to facilitate many withdrawals. When you consolidate leftover small inputs, you do so at opportune moments with low feerates, and the many smaller inputs easily outweigh the creation of one heavier output on your consolidation transaction. When you do have to make a transaction at a high feerate occasionally, it serves you well that your inputs are cheaper. Conclusion: P2TR is cheaper in almost every scenario ---- While especially exchanges are still dragging their feets to enable support for sending to P2TR outputs, just from a cost perspective, P2TR ends up being cheaper in almost every scenario. Additionally, if you need to create transactions at high feerates occasionally, the lower-weight inputs will save cost. [1]: https://i.sstatic.net/DXpr7.png [2]: https://i.sstatic.net/BxaDD.png