# Why do we titrate from a colourless solution and why should we remove unused sodium hydroxide from the burette as soon as possible?

In my lab we performed an acid base titration, where NaOH was used to titrate a standard solution, potassium hydrogen phthalate (KHP, or $\ce{K+C6H4(CO2H)(CO2^-)}$), using phenolphthalein indicator.

Why is it preferred to titrate from colourless to a pink solution rather than pink to colourless?

Also, why is it advisable to remove NaOH from the burette as soon as possible after we are done titrating?