In article , "mo"
nospam says...
Grippers - do I need them?

Not if you want to do a crap job.

I plan to just roll out the underlay and then just roll the carpet on top -
and if needed knock in a couple of nails in all corners to hold it in
place - a few carpet fitting guides I am reading online suggest grippers as

Only a few?

it will stop the carpet from having 'bumps' when you roll furniture onto
it..... the carpets fitted aroudn the house that were done by pros do have
gripeprs and look nice, equally carpet around other rooms don't have
grippers and look fine (but dont have udnerlay - which is what will make it
harder)

What difference will that make?

Suggestions?

Use gripper.

I don't much fancy buying loads of rods of grippers - can you get away with
having one every 2 metres or so, or is it suggested to keep a continuous
line?

Why don't you want to do it properly? Carpet gripper is cheap and makes
it much easier to lay a carpet so it looks good and stays looking good.
Also use a proper metal strip for the threshold so it stays flat and
doesn't fray.