How long is a peice of string Benny?

It is not only the number of days to its last run that matters, but also how many runs in this preparation it has had. Also, the distance it is running at.

Some broad guidelines are:

up to 1100m: Check to see how the horse has gone at its last two 1st/2nd up run. Days to last run are maybe not so important with the shorter distances, more a case of how hard a horse has had at a previous start and sometimes for this reason, a sprinter might need as least 21 days to recover, sometime longer as they can be flattened by too hard a run.

1200 to 1399m: Normally at least two runs in with the last run being within the last 21 days.

1400 to 1599m: Normally at least three runs in with the last being within the last 21 days.

1600 to 1999m: Normally at least four runs in with the last being within the last 14 days.

2000 to 2399m: Normally at least five runs in with the last being within the last 14 days.

2400m plus: Normally at least six runs in with the last being no longer than 14 days, but preferably 10 days or less.

However, you need to check to see how a horse has performed in the past as some may be able to move up in distance earlier in their prep than others - history tends to repest itself in this regard.

Also, some trainers are very good at moving their horses up in distance quicker than others. Gai Watehouse is one, who regularly runs her horses 2nd up in a perp with success, going up in distance 400m or more, ie. 1st up at 1400m with a 2nd up run at 1900m or 2000m.