It’s the fees getting charged in the Mempool. Go to Mempool.space and you can watch blocks get mined. If you have a bunch of UTXO’s on chain, when fees are low it’s a good time to combine them. This is the lowest it’s been in a long time.
In theory, the fees to spend them would be cheaper later. I’m no expert, but that’s my understanding. 🤙🏻