So when do you give up on a system ?

The answer is - there is no answer (IMHO)

As i said somewhere else i have really good and deep horse racing form data that goes back in different periods over 20 years back to 1993.

originally it was part of a quite sophisticated database that was called TK-TOOLS.

In that time i developed systems that would win for 2.....maybe 3 years and involve analysis of '000's of races and 10's of '000s of horses and would extract enough starters to win handsomely ( say 15% POT) - I would be saying - eureka - this is it - i have found it.....but then they would start to get wobbly and then plunge into oblivion and never recover - for no apparent reason.


Others would be rocky from the start and come good for a while and then drop back.

I couldn't work out what changed and couldn't find any filters etc to trim the dive.

In the real world now - I am going through a rough patch right now with my selections. So much so that I have cut my bet size to preserve my bank and be there when the improvement comes (if ever).

What I have done also is examine my results at a deeper level.

In my data I obviously record the results and the dividends etc. – but I go 1 step further – I record the beaten margins for all starters.

What I have found is that whilst my win POT is negative my about 20% ( down from about +10%) - my selections finishing within 2 lengths of the winner are only down slightly – at this point I am hoping that the negative POT is an anomaly and they are thereabouts – but just not winning and that it will improve later on.

Hope springs eternal as they say.

So that might be one way - analyse your actual results and see how close they are.
Maybe you are just getting beat by bad luck - which could eventually turn around.