Indentation is pretty low on the list of things that make code maintainable or not. (If it bothers you, just pass the code through a pretty-printer.)
Much more important is to pay attention to system-level measures such as modularity, abstraction, (de)coupling, and documentation. 99% of maintenance nightmares are due to code that is not modular (and thus not easily replaced), is abstracted too much or too little (leading respectively to obtuse or repetitive code), highly coupled (causing brittleness when assumptions are broken), or poorly documented.
(There are probably others, but these are the first to come to my head. These measures are also not necessarily orthogonal.)
Much more important is to pay attention to system-level measures such as modularity, abstraction, (de)coupling, and documentation. 99% of maintenance nightmares are due to code that is not modular (and thus not easily replaced), is abstracted too much or too little (leading respectively to obtuse or repetitive code), highly coupled (causing brittleness when assumptions are broken), or poorly documented.
(There are probably others, but these are the first to come to my head. These measures are also not necessarily orthogonal.)