To high a volume while recording is what should be avoided at all cost. Too low of volume is avoided by increasing the bit depth of the recording. So it becomes a question of the bit depth of your audio interface and your audio program.
You should use a program with internal 32bit floating point audio like ardour. This will allow you to adjust levels in post more easily without loosing anything.
In practice 24bit audio on your interface is enough that you can record with plenty of headroom as they call it in the business. This means that you usually won't even worry about the low level being captured because with enough headroom it is there. However you may be concerned about the signal:noise ratio. In practice you should be aware of the dynamic range of the instrument or environment you are recording. Let's say a bass guitar has around 25db of dynamic range. You'd set your peak on the trim so that it peaks 5-10db below that.
The disadvantage of using higher bit depth is you have to dither your recording down to whatever level you want. For instance CD's have 16bit audio. Typically if you decide to record at a lower bit depth you will need to use a mixing tool to compress the dynamic range on the fly. Sometimes people even set a hardwall limiter on each audio track just in case there are one or two sounds that go over 100% (a special form of compression). The disadvantage of a limiter or compression is they can distort the audio, so setting the trim correctly is a matter of experience. This is one of the reasons a band will do sound checks.
Welcome to the wonderful world of audio engineering :)