Every gym has a shelf of things that run out at the worst possible moment. At our Samford gym it is usually tape, chalk and whatever oil we use on the leather.

We go through a fair bit of castor oil, mostly on the leather gear. Boxing gloves, lifting belts and the old medicine ball all get a thin coat now and then to keep the leather from drying out and cracking. A little goes a long way, and it is a lot cheaper than replacing a good belt. We also keep some for the squeaky hinge on the roller door, which seems to need it every month.

Buy it like a coach plans a block

Good coaching is about timing, and so is good buying. You do not peak in week one of a block, and you do not need to buy on the first day of a sale either.

Propel Health is running its Black Friday offer in three steps:

• Week one, 9 to 15 November: 10% off
• Week two, 16 to 22 November: 15% off
• Week three, 23 November to Cyber Monday 30 November: 20% off

If the shelf is empty now, buy in week one and get on with it. If you can wait, the deepest price in the castor oil black friday sale lands in week three. Either way the discount comes off automatically, there is no code, and it stacks on the pack prices.

The numbers for a gym shelf

For us the 500ml bottles are the obvious pick. A 500ml 4 pack is $122.95 normally, which is two litres. At 20% off it comes down to $98.36, around 4.9 cents a millilitre. That covers a lot of gloves and a lot of hinges.

If you only need a little, the 200ml single drops to $21.56 in the last week.

What we look for

We like that it is certified organic, cold pressed, hexane free and in amber glass. There is nothing added to it, so there is no fragrance hanging around the change rooms.

Small business to small business

Propel Health is Australian owned and based in Brendale, a short drive from us. Free standard post applies on orders over $125, and orders go out in 1 to 3 business days.

A tip for the leather

Wipe the gear clean and let it dry first, then work a few drops in with a soft cloth and leave it overnight. Too much oil just leaves things greasy, so start small. We do our gloves and belts at the end of each term, and the same 500ml bottle lasts us a long time.

Plan the buy the way you plan the training: know what you need, pick your week, and do not panic at the first countdown timer you see.