It is better to ask your cobbler which options you have. For durability and aesthetics, you just cannot beat the re-sole. If the leather has become dried over and cracked there will likely be a need for another pair. When you have a leather sole a half-sole might be a cheaper alternative but it really takes an expert to switch to a new half-sole. These repairs may be more costly than boots themselves but would be worth it if it was a well-loved pair of boots.