> Commercially available radar reflectors are frequently found as a sailboat supply item

Wooden and fiberglass boats are fairly invisible to radar, even with metal masts and rigging. If you are ever planning to head out into the ocean and near where you might expect commercial shipping, these are a cheap safety item for making your boat visible.

If you attempt to go near larger commercial shipping lanes you are required to have them at least were I live, they are not optional here. Also get the right size, some smaller ones are useless (so I've been told).

> If you attempt to go near larger commercial shipping lanes you are required to have them at least were I live, they are not optional here.

Not required in the US, but not a bad idea to hoist one in fog.

Although these days, an AIS transmitter is a better answer. But a prudent mariner never trusts a single point of failure, so might as well do both.

Admittedly I don't always hoist the radar reflector in the heavy fog near the Golden Gate bridge, but I always transmit AIS in low visibility (and monitor it).

I think the standard for marine radars on oil installations around here (norsok) was to be able to detect a large steel target at 25 nm.

It is now 8 years since I worked with it last time and 1000m2 sounds very large to me but that is the only number that pops into my head.

So yes, if you are in a small boat, use a radar reflector and also be alert.