It depends how much time you invest. I didn't pretty well for 30 years without a bikefit. But I've also had bikefits and physio consultations that have helped me sort out issues that appeared when my volume increased massively. There's also people who seem to have fitted themselves into horrible positions and caused themselves numerous issues as their fits got weirder and weirder over time to cater for the muscle imbalances they kept exacerbating.
Basically, it depends. Picking a saddle doesn't need a bike fitter, but it might help.
It depends how much time you invest. I didn't pretty well for 30 years without a bikefit. But I've also had bikefits and physio consultations that have helped me sort out issues that appeared when my volume increased massively. There's also people who seem to have fitted themselves into horrible positions and caused themselves numerous issues as their fits got weirder and weirder over time to cater for the muscle imbalances they kept exacerbating.
Basically, it depends. Picking a saddle doesn't need a bike fitter, but it might help.