The cost of running a pump for your well and maintenance costs are subject to conditions of the well itself and the costs of electricity in the area you live, compared to water. If your well should run dry and you had to put in another, that would blow up any estimate you could make. Being well informed on how other area wells perform will be your best friend in decision making.
Septic systems are also very different, depending on soil conditions, age, etc. In Vail, Az, the recommendation is that they be serviced every 5 years. In my 18 years in Real Estate, I have only had one septic system need a whole new leach field during inspections. Most run relatively symptom free for years. Consult a local septic pumping company for their recommendations.