Remember the hidden agenda- saddlers want to sell saddles, so dont be swayed into buying the dearest/one with the famous logo/new technology/ - its all a variation on the Loreal 'because you re worth it' line .
I have no time for synthetic [ dont last five minutes and dont sit well] or treeless [ why not a felt pony pad - or even go bareback] or these reinventing the wheel jobs which are a 19c cavalry saddle with knobs on.[ the endurance types]
Its many years since we bought a new saddle - secondhand much better for comfort, and good brands will last decades. having backed many horses a 40 yr old Barsnsby wide GP has fitted 90% of them!
We also have Podiaskji of that vintage for dressage- not as padded as newer saddles , but I hate bling!
Jeffries Working hunter for show/hacking/hunting. Various others come and go as needed.
The 2 Anthills [1 dressage 1 VND] are my favourites - for showing/hunting etc. One xwide ,1wide. The xwide was bought off ebay - fits horse and myself like a glove!
I would recommend you go to a good saddler with a large 2ndhand dept and ask to be fitted with a second hand saddle by them. Then if shape changes etc , you ll not lose too much money.