|A Brooks B17 saddle will last for decades if looked after .|
Buy some Proofhide
This is the only leather dressing Brooks sell or recommend. Whilst it might be possible to use alternatives, I don't know what there is to gain. A tin costs £7.95 and lasts for years.
Apply Proofhide underneath the saddle liberally when the saddle is new. It is easy to do this before it if fitted to the bike. Don't polish it off, simply allow it to soak in and feed the leather. Also apply a smear of proofhide to the top of the saddle frequently when the saddle is new. Use a clean soft piece of cloth and allow it to dry off over night. Remember to "buff" it before you ride it - just like polishing a pair of shoes.
Buy a tension spanner
Again, it is not impossible to find another way of completing this task, it is easier when you have the right tool for the job.
When a saddle is new, it needs to be tensioned fairly often in the early stages. I used the spanner and turned the tensioning nut one quarter of a turn every two or three weeks. It might be tempting to do more but you run the risk of stretching the saddle too much and too far. Just take it easy - if you over tension the saddle, it won't shrink back so please be conservative with it.
Once the saddle has "broken in" and moulded itself to your shape, it will be a really comfortable saddle that should be a joy to own. This will take a few hundred miles to gradually complete this process. Once it is broken in, I think only very occasionally should you ever need to tension the saddle. Remember to only turn the nut by 90 degrees at a time.
Keep it dry
It is best if the saddle can be kept dry and so you might want to consider protecting it if it's likely to be left outside for any length of time - i.e. at a campsite, on a car rack etc. If it does get wet, let it dry out naturally - NEVER use a hair dryer or anything like that. If you do, you might as well buy a new saddle! Also, if at all possible, try to avoid using it if it is very wet. Once dry, that should be a prompt to give the top a smear with Proofhide.
Experiment with the position of the saddle
This takes a little while in my experience to get right. It involves a bit of trial-and-error and well worth persevering with - getting the tilt right along with the forward / backward position.