Ok, so I do the prudent thing and hold my cryptos in my ledger nano-s.
Then I decide to take profits in a rally and transfer my stash to my exchange of choice.
I started with XRP and the trip to my exchange was almost instantaneous. Then came LTC It's bad enough time has been proven to slow down when you're in the midst of a crypto transaction but it seemed to take forever.
It turns out that the average speed for XRP is 4 seconds and 30 minutes for LTC.
This is a great article detailing the average speeds of top cryptocurrencies.