Titration of acid with base or base with acid: can I always use the same indicator? If you are doing a titration with $\ce{NaOH}$ and $\ce{HCl}$, does it matter which one goes in the burette, and will this change the outcome of whether the solution in the beaker will turn pink due to phenolphthalein?
When phenolphthalein is used as an indicator, NaOH is taken in a burette because then the colour change is from colourless to pink. And this time, it will be easier to observe.

On the other hand, if HCl is taken in a burette, colour change will be from pink to colourless which can't be observed in a single drop.

When NaOH is titrated with HCl using methyl orange as an indicator, HCl is taken in a burette because then the colour at the end point changes from yellow to red which is easier to observe rather than that from red to yellow.