We have between 5-15, iv been eating between 12&15,
Is it better to eat less or more?

I always think it's better to eat more to be honest. Using the Syns helps to avoid those feelings of deprivation that can occur if you don't use many Syns at all.
Some people use 5 a day during the week, but then use more at the weekend so they don't feel like they're missing out on something, either alcohol or a takeaway or something, whatever they feel is necessary.

Don't feel like you have to use all of them everyday though, if you don't want to use them, don't force them. But just know they're there if and when you want to use them

Yeah a lot of people have said to eat more on Instagram a lot of people have been posting that they are ending the day on 1 syn, but maybe they save them for the weekend

I've done that quite a few times. Today I've eaten my full allowance, but tomorrow I could end the day on 5. It purely depends on what my mood is
I eat them if I need to, but otherwise I can quite easily eat very few but 99% of the time I will use the full 105 a week.
It's all about what works best for you

i agree, just use what you feel necessary, as long as its working for you then thats all that matters