Quality is delighting customers
This might help you,
1)Internally check that some actions (like "close file") do recover some memory and log it?
2)Assert on memory state inside our unit tests (but it seems this would be a tedious task) ?
3)Manually regularly check it from time to time?
4)Include that check each time a new user story is implemented?
can u be more precise..
This might help your if you are using .net project - http://www.codeproject.com/Articles/19490/Memory-Leak-Detection-in-NET
I mainly test on Windows operating Systems - I wrote a tool that uses the perfmon.exe.
I start my automated tests & watch different perfmon counters and write them to a logfile. From the logfile I automatically generate reports, where I can verify wether there's a performance Issue, memory leak, ....
I'm sure that there might be better ways/ tools to measure the performance - but it fits for me. :)
Developers even use task manager to understand how much memory is sued by a given function and if more than one instance of the project exe is seen in it. Perfmon tool as said by Peter can also be used to verify performance issue.