You can use default 1.52 for all of them.
Non-metals vary only very little in specularity. The range rarely goes above >2. Lesser reflective like water start at 1.333, most woods, bricks, fabrics and even plastic are around 1.52 or slightly higher.
No magic here.
{not that it matters, but if it isn’t measure here, you will not get exact number. Like expected, it’s mostly liquids, crystalics,… Refractive Index Database | KLA }
That’s why I never work too much on personal works. I accept shortcomings and move along to next thing, long before ‘diminishing returns’ (too much effort for little progress) occur.
It’s easy to get lost, loose focus and energy and waste time and effort. Better to complete something, learn from it, but put those learnings into use in next project. Sometimes…quantity matters :- ).
Do you make an effort to try new techniques? I mean, how do you measure your progress?
I do focus on goals, but not ‘techniques’, or perhaps I don’t share the same understanding of the word.
I don’t particularly measure progress either, but looking back I try to judge my results. Everything to me is rather one big ‘picture’, and I do rather try to not get lost in individual facets.
By techniques I mean: exploring new ways to achieve better results. But, I see what you mean and I think that is perhaps the best way to “progress”. I do keep track of the new things I learn, so I can use in the next project.