Dracaena leaves are starting to turn yellow then brown,

Yellowing leaves on an indoor plant can either be draughts from open doors/windows. OR it is too wet!

'Too wet'. Can be very different according to season and temperature. For instance most of my plants kept under glass do not receive a drop of water between early November and late March when new growth becomes visible. That's not my requirement, it is dictated to me by the needs of the plants.

All too often people are tempted to add water too early in the spring time and the plants quickly rot despite having almost come through the winter without harm.

I have had a number of these plants myself over the years and, while there may be a possibility of over-watering, it is more likely to be the natural shedding of lower leaves as the plant matures. They all lose their bottom leaves as they grow taller - and they will turn yellow, then brown. I regularly pull off the brown leaves from my dracaenas.