bcaz

If I upgrade to a 1x12 speed cassette from a 1x10 speed cassette can I replace the freehub so I can use a 12 speed or do I need to replace the hole hub and do I need to replace the derailer and shift handle i am starting with a gaint sport 32h I think it is a standard hub or Shimano hub

cpach

Some hubs have replaceable freehub bodies. Probably a stock Giant hub won't. You can use a NX Eagle or some SunRace cassettes with a 12 speed drivetrain on your existing freehub. Shimano doesn't make a 12 speed cassette for a standard HG freehub body, but the spacing is basically the same as Sram/Sunrace so you could run an otherwise Shimano drivetrain with SRAM compatible cassette, chain, and chainring if you really wanted to.

rosefarts

This is one of those things that very possibly just isn't worth it.

New hub+rebuild or new wheel, new shifter, new derailleur, new chain, new chainring, and new cassette. Everything is new and not on sale.

Have you considered SLX Shadow 11 speed? That's what I did. 11-46 sunrace cassette and it fits fine on the hub you already have. SLX derailleur and SLX shifter. I actually used Microshift 11 speed thumb shifters because I don't know what's good for me, good news is that the regular shifters cost less than my goofy retrogrouch ones. New 11sp chain will fit the NW ring you already have.

Its still not simple but it's like $200 cheaper than 12 speed right now and simpler.

Think about it.

Cyclist0108

My kid just upgraded from 12 speed to Microshift Advent X 10 speed. He is very happy with the improved performance, after having gone through two GX Ealgles and then two Shimano 12 speed derailleurs.

aggiegrads

If you are looking to increase gear range, Shimano quietly came out with large range 10 speed cassettes in 11-42 and 11-46. Check out the m4100 range. You can likely upgrade for the cost of the shifter and cassette; less than $100.