On the apnaDatabase home page, you can see 'Recent searches' and 'Saved searches' on the right hand side.
The major difference between 'Recent searches' and 'Saved searches' is that any of the 15-18 filters as visible in the below screenshot, applied by you on the search results page on the left hand side will not get auto-saved in 'Recent searches'.
The way you can experience this is, if you click on any of your recent searches, you will see that any of the 15-18 filters you applied need to be applied again. However, if you click on any of your saved searches, you will see that any filters you had applied in this saved search get auto-applied.