Do as many pull-ups as you can then, after a rest, try to repeat that number while wearing your harness, rack and rope. Notice a difference? A large, old style rack can add several more kilos of power-sapping load to your poor fingers. So minimising the weight of every piece of equipment makes a lot of sense. After all, saving grams is the easiest way to improve performance, probably having a far greater effect for most of us than hitting that campus board.
saving grams is an easier way to improve performance than hitting that campus board
The quest
Start by searching around for the lightest gear known to man. Check out equipment catalogues, (but don't be surprised if manufacturers' claimed weights aren't totally accurate) talk to shop staff and look at what other climbers are using.
A saving of 10 grams on a wiregate karabiner may seem insignificant but if you're looking at replacing all your old chunky 'krabs', that 10 grams might be multiplied by say, thirty pieces, and that becomes a total weight saving of 300 grams. All of sudden it starts to make the whole quest for weightlessness - and its expense - much more worthwhile. Question every piece of equipment you have. Do you need such a chunky, overbuilt harness? Could you replace that fibreglass helmet with a foam one that is 50% lighter?
Unfortunately, the lightest equipment is invariably more expensive. So you'll have to decide for yourself whether or not the weight-saving is worth the expense. Ensure too, that durability and safety are not compromised by going too light, and you will have to accept the cost of replacing ultralight components more frequently.
Database
In climbing your power to weight ratio is all-important, so consider your own diet and see if you can lose a kilo or two to improve your statistics and performance!
It may sound anal, but a good way to work out what needs replacing or leaving off the harness is to make a list or database of all your climbing gear, and note the weight. You may be surprised at how heavy some areas of your rack are.
Ropes
Don't forget ropes. These can be a significant weight, although they have improved massively over the last five years, becoming stronger and lighter. The new norm in half ropes is now 8.5mm or even 8mm and the old workhorse 11mm single can be superseded by the slinky 8.9mm.
And the rest!
If you like multi-pitch rock routes in the mountains, look at the weight of your waterproofs. Do you need to carry that heavy, bombproof Gore-Tex jacket? How often do you actually wear it? Perhaps a lighter alternative would be to buy a lightweight windproof jacket designed for running or cycling or even a cheap, featherweight, non-breathable jacket from the local market. Do you need to carry your rock shoes all the way to the crag, and then carry your walking boots up the climb? Perhaps you could just get a modern pair of approach shoes or scrambling boots to wear to whole day if climbing long easy routes?
Weight saving without cost
Of course, there are cheaper ways to save weight. You can buy all the titanium or carbon-fibre gizmos available - but do you really need them? Do you need to carry that Hex 11, or perhaps you can replace it with something else, like a lighter Rockcentric? Do you really need three Wallnut 10s on your rack? Carrying less hardware is usually a lot lighter than carrying a lot of lightweight hardware.
In climbing your power to weight ratio is all-important, so consider your own diet and see if you can lose a kilo or two to improve your statistics and performance!