They really do need their claws cut (brace yourself they are little gits )
They don't do enough on concrete to wear their claws, you need to protect their feet too on concrete, give them a bit of carpet to retire to. They have quite delicate paws , not like rabbits which are more fur not pads. If their claws get long, they walk on the back of the heel and can cause fractures. And if you look at their front paws, the 'pnkie' claw tends to turn inwards and can dig in.
You can either take them to the vet or a local guinea rescue which offers claw cutting for a donation. Or arm yourself with small animal nail cutters (they need to be sharp so you don't crush the claw) some cornflour in case you have a bleed , and a towel to wrap them if they're wriggly. Best with two people, one to hold, one to clip.
Trim the opaque end, it forms a point with a little 'ridge'. You can always trim a bit and go back another day (We often do front or back one day). Much easier with pink clawed hogs.
Depends on growth, ours maybe every 3-4 weeks but the curly claws every 2 weeks. Ours walk on soft surfaces all the time so they don't wear.
If the claws are long, cut them regularly to shrink the quick back, if you cut the 'live' bit, you'll get shrieked at and they bleed well. I caught GP4s claw a while back, she was uber judgey (even though we stopped it with cornflour and I told her that vets use a claw bleed to take a blood sample) . I felt soo guilty for ages