Do I need archive_mode = on for hot standby?

Hi there.

I'm planning on setting up a master database and multiple hot standby slaves using streaming replication.

If I use a large(*) value on 
wal_keep_segments
do I really need archive_mode = on then?

Any potential problems with this strategy I should be aware about? 

(*) With large value I mean a value such that a failed slave will be up and running again (with a few days margin) before the master server starts to clean out old WAL segments.