I took care of my first curry leaf plant which is 9 year old, having compacted soil and a lots of roots packed in the pot.
I realized that curry leaf plant should be taken care when growing ambient is hot as to the plant is originated from tropic climate.
I removed the roots outside by a few centimeter (about an inch) with a pair of scissors. You can tell the soil is almost dry except top layer, so that water is not fully and evenly distributed into the roots. I also rubbed the bottom of the roots to loosen the soil.
After that, I put large sized coarse clay soil (called Akadama) for better drainage and aeration in the pot.
I also reused the trimmed roots to fill between the plant and pot as to they will be eventually turned to humus and retard compacting the soil. After filling the clearance with the coarse soil as well as the trimmed roots, water the plant well.