Issue about selection of Tor relays when using the default torrc configuration

[Sambuddho Chakravarty]

Hello All
 I am using the default torrc without giving any information on what 
relays to select for circuit creation. But apparently tor (from what I 
experience) Tor doesn't change the relays selected in a long time. So 
each time (over a period of 2 - 3 hours) I start the tor client it seems 
to be selecting the same relays  . Is there a way I can ensure different 
relay selection over each time I start the tor client.

Thanks
Sambuddho