the reason hoses dont last that long is because every time you squeeze the lever the pressure inside the hose pushes against the inside of the hose forcing it to be slightly wider. all of these 'pressure pulses' cause the walls of the hose to become weaker and they expand more with each brake pump. this means that you will need more fluid per brake and therefore loose power. well not loose power but lose brakeing efficiency and will need to move the brake lever more to achieve the same stopping force. this is what is giving you that spongey feeling you were talking about.
also, if your pads are worn down quite a bit that too will mean you will have to squeeze further on the lever.
also, clean your calipers and make sure there is no crud preventing the pistons moving as this too will mean that you have to push the piston against the crud and brake pad and could make it feel spongey.
to slove this problem i suggest topping up your brake fluid, cleaning your pads and caliper assembly, and upgrading to a full steel braided brake hose system, and possibly getting some EBCdouble HH brake pads, thats hat ive got and they bloody excellent
hope this helps
TRICK
