William Naismith's rule

Naismith's rule. A basic planner for figuring out how much distance a reasonably fit person on reasonably friendly terrain can cover. Then a guy named Tranter added a bunch of corrections for age, etc. This all came up in a conversation with Kevin McLane, surely one of Canada's most prolific climbers, writers, and general "give 'er" kind of individuals.

I have a few rules like this as well. General rules (with tons of exceptions).

Ten pitches of climbing fresh ice will pretty much take all day.

I can generally run about ten minute miles on almost any trail out there if averaged over the course of a few hours. Except when I can't.

Ten pitches of gear climbing at my trad standard will pretty much take all day.

Any approach not involving trails will generally take a "practice" approach to find the way in.

Eat every hour at the minimum or suffer.

Take twice the food and half the water in winter as you do in summer.

If your winter pack is bigger than 45L you're backpacking, not climbing fast.

A pack smaller than ten liters is a purse.

The farther you are from home the more you'll get done in the wrong conditions.

Put another way, visiting climbers are often stronger than the locals...

Camping is vastly over-rated. Most local trips can be done without camping.

As you get older your potential for injury while doing new sports increases and is inverse to your ability to heal from an injury...

And so on, this sort of stuff is fun for me to geek out on.