I guess it depends on the particular system. My clock/date time can take a little while to change back but it does change back. Double-check it from time to time to see if it's changed back.

How long to leave BearShare running? The longer the better! This helps build up a good bs connection list and also lists your client as being a client that connects for good periods and is more inviting to connect to. I see clients that stay connected for many days non stop. But they run as Peers. And they are invaluable to the network, especially for other BearShare users. BearShare shares its own list of best BearShare hosts to connect to. Some of these run as Leafs from time to time.

The same is true for any gnutella client. The longer you leave your program running, the better you are seen overall on the network, and the better the program should run after it's been connected for some time. If running as a Peer (ultrapeer), then UDP host sites will list you highly if you stay connected for long periods. Thus you would find it easy to connect and others would seek to connect to you. The longer a gnutella program has been connected to the network, usually the better the search results. (Unless you are unluckily surrounded by spam peers/hosts.)