what YOU are comfortable with.
components wear with use so it makes sense that the longer they are running the more they will wear BUT it is also true that components receive considerably more "wear" through surge when they are initially powered up so the "wear of parts" arguments are a wash.
The amount of power used is negligible and again, there is a surge upon start up so power concerns are essentially a wash also.
Depending on components and system settings it can be MUCH faster to access a computer if all you have to do is turn on the monitor rather than waiting on a full boot - doesn't always apply however so that applies to only certain specific set ups.
Regardless of your personal decision, I would suggest turning the monitor (CRT) off as it does tend to generate a lot of heat and use a lot of power.
Unless it is someone else's computer and they have told you what they want, there is no right or wrong answer despite the many long and tedious discussions on the pros and cons either way.
It just boils down to what YOU are comfortable with.
I know just enough about computers to get into trouble from time to time. I know everyone has their own opinion about things and very often I have to rely on what others tell me. which is better for the overall life of a computer. My use of a computer may be as much as several time a day down to once a day and for anywhere from a few minutes to a 3 or 4
hours at a time. My question is: Is it better to turn it on and off each time I use it or leave it on (in a standby state) all the time? Thanks (in advance) for the input.