An all important question is "Does this horse have any improvement left in it? or did it peak in that run?"

Its always to better to back the horse on the way up rather than the way down. The
odds are a lot better on the way up as well.

You might spot a horse at 8/1 or 10/1 that is on the improve - you back it and it wins. Next start its 4/1 - you back it and it wins again. Next start its 2/1 & got more weight so you don't back it- it loses this time and some punters wonder what happened?????