Having difficulty reading measuring lines on your water/drinks bottle?

I was chatting very recently to a former fellow walker and camper, who often struggled to read the faded measured marks on his drinks bottle, particularly at night. Whilst camping on a bonafide campsite, I teased him, and offered the use of some elastic bands I had in the car. The conversation also led to him revealing that he also had an old water bottle for toilet purposes.
But I'll not go any further with that one,  other than to say, make sure your bottles are clearly labelled.
So, if you have difficulty reading measuring lines on your water/drinks bottle, what can you do?
If you use different colour bands or sticky tape (electrical insulation tape is ideal) set at different levels, you can quickly see where the required fill line is, and no searching for your glasses...
Not so good for those who are colour blind, but you can use different thickness bands.
For those with memory loss, I'm sorry, I've forgotten!   


Flickr Peak Rambler