How often is Windchill restarted at your company?

We usually only restart when some type of maintenance is required - either a critical patch set is installed or some property needs to be changed.  I'd say this happens on average about once a month.

WC 10.2 M030 / MS SQL 2012 / Windows Server 2012

In an idea situation Windchill rarely needs to be restarted, but it can also depends on the OS on which it is running too, or other factors.  Windows systems occasionally get updates that require server restarts, thus requiring Windchill restarts too.  It isn't so much that there is a "correct" or "expected" frequency, but rather what is optimal for your installation.

Other factors can also influence the frequency of restart too, such as backup strategy.  I have worked with customers that range from only doing restarts as necessary for maintenance updates or code changes, to a weekly cold backup done on Saturdays requiring WC to be down for the DB/LDAP dump, to performing restarts every night at midnight, with Windchill down for a few hours each night for daily cold DB/LDAP dumps.

I'm interested in your comment in that you see "no connection can be found" warnings repeatedly in Creo.  My company provides Windchill maintenance and monitoring services, and we'd be happy to provide an assessment to get to the root of this issue or other issues you are experiencing.  If you are interested, please send me an e-mail at robert.sindelar@eccellent.com.

We shutdown every night with a script.  The script shuts down the windchill related services, backs up a few critical files, cleans out some cache files and restarts Windchill.   Overall the process takes ~10 minutes.

We implemented this procedure at the advice of our VAR/Consultant and I have to say, we have seen very few Windchill issues, and the performance is pretty stellar.

Also restart every night, also have good results with performance and stability.

We do the same as described by Marc.

We also restart Windchill every night to align some attribute (selectable from a drop down list) shared with our ERP (which is master for this attributes).

We also restart every night by way of a backup script. 

We do maintenance monthly.  But I do not think this is going to solve your problem of no connection can be found.  We had a similar issue. What version of Creo are you using?

We also shutdown Windchill every night. We do it so we can make a cold-backup. We dont want Windchill running when doing the backup.

We run 24 hrs/day during the week so we restart every Monday, Wednesday & Friday @ 5am

We only restart in case of updating the software - so maybe once in 2 months. Making a Backup can be done within oracle without shutting down Windchill.

Shutting Windchill down also has the risk that someone is working within Windchill and things get messed up. I can't see any reason why it should be safer to shut

If you have problems like " "no connection can be found, do you want to work offline"." you definetly should contact the PTC support to sort this out.