Well there's a Keyboard Shortcut for incrementing the text size. I think it's CMD > or CMD <
Might be wrong I'm just so use to doing it.
And in the preferences of InDesign there's a section under Units and Increments to set the amount it increases or decreases for both text and leading (I think).
Sorry don't have it open to check.
Also, using Styles, you can edit the Style and increment the text everyone on the document in one go.
For example, I make the body text style and set the font size to 9pt.
Then all other styles are Based on Body Text (in the Style setting for new styles)
So bullets/indents/numbered lists etc/ even some headings.
Then when I need to increase the size of the text - only edit the Body Text style and it increases all other styles as they are Based On this style.
Changing the settings in any of the styles breaks that relationship - so if you need a header style with larger font - you can increase this font size here in that style - and it won't be linked back to the Body Style for font size only.