Sand comes from the well because the well screen and/or the gravel pac is not right. Bigger pump, more water, more sand. Pumps cannot take this kind of sand very long before they are destroyed. You can add a bigger filter or a sand trap but the pump is still being destroyed. My rule of thumb has always been, if the pump will last atleast 5 years, you can afford to filter the sand. If the pump does not last 5 years, it will pay to get a new well. I would guess your pump will not last 5 years. In our area we guarantee sand free wells. We use small screen or perf casing and very small gravel pac for filtering the water as it enters the well. This is the best place to filter because your pump never has to pump the sand. "Redeveloping" probably means the well was bailed out a little. Don't think there is anything they can do to the well screen unless you have big enough casing to run a liner with a new screen. ie; 6" casing with 4" liner and screen. Sounds like you need a well driller. Just as well fix the problem as anything else is a non stick band aid. Might be a hole in the drop pipe or excessive cycling, but you should have noticed other problems if that were the case.