Never delete - rename first!
In 2016 the hosting provider 123-Reg deleted 67 customer servers due to a bug in a script. The script checked should delete inactive servers, but the check was faulty.
Read more: http://www.availabilitydigest.com/public_articles/1104/123-reg_outage.pdf
For files: rename/move file first
For VMs/Services: shutdown first
Delete only after you verified that everyhing is working fine!