Yeah, don't worry about it too much. Just give yourself plenty of headroom so you don't even come close to clipping. In this day and age, the one of 24/32 bit audio; it's asinine to clip anything. There's so much headroom.
One good thing to keep in mind is; even the best converters will start to distort in some small way beyond 3db below 0dbfs. That means when your master meter peaks at -3. Chances are, you don't have anywhere near the best converters anyway, so you're dealing with an even stickier situation.
Amping up your mixes too loudly is kind of like running a car engine floored in neutral. There's no functionality, yet the technical aspect of your device/machine is being strained unnecessarily.
Feel confident in your recordings. Glance at your master meter. If it's hitting too hard, drag the fader down, and turn the volume up to a reasonable level on your playback system. Don't use your mix to give you the volume you think you need. Be in control. Loudness has nothing to do with the amplitude you can give your mixes.
Let the mastering engineer get things up to a competitive level. They know what they're doing, and we have a focus on doing just that.
Playback level is important. Listen to your favorite music and have your friends sit next to you. Can you carry on a conversation? You should be able to with maybe a slight amount of elevated voices. If your playback system sounds like a rock concert and you have to yell, it's way too loud. Your mixes won't come out properly. If it's too quiet, you'll be tempted to mix louder, which is detrimental to your sound.
Trust me. I want the best not only for you, but for music and audio at large.