Bushwalk Australia

There's three ways that a jacket can be closed:
1 Zip.
2 A flap or flaps on the outside with Velcro.
3 A flap or flaps on the outside with studs.

Zips are nearly universal. How heavy does the zip have to be to be functional?

The zip often has outside flaps to keep out water. Is it best to have Velcro or studs on the outside flap/s? If Velcro, should this be a continuous strip (keeps out water better) or with small gaps (easier to undo)? Some jackets have a single inside flap with no Velcro or studs. Does this flap serve any purpose?

TIA

Storm flap should always close with studs at top and bottom. Mid body can have two or three short bits of velcro, but velcro above or below that is a pain in the everything when you're packing up or pitching.

Forget the velcro and go the studs I reckon.

on some garments the inner flap is folded at the end to reduce any water getting through the zip rom getting past the end of the flap and forcing it to run down the inside of the crease, some zips are water resistant with an outer polyeurethane coating that meets up when the jacket is zipped up,
there are a few jackets with proper waterproof zips like the top end Mountain Equipment jackets but they are very expensive.
if you're going to be in a lot of heavy rain in cold weather you ideally want an outer storm flap, but most jackets dont come with them anymore and rely on the water resistant zip. velcro is becoming relatively rare.
and +1 for studs top and bottom on the flaps...