I was meeting with some clients with whom we’ve had a long, ongoing relationship (designed and built their house, then an addition and a barn/garage, maintained both through the years) to review a just-completed inspection report. The house is 20 years old so we had produced a document outlining the major maintenance to come and predicting when various measures might make sense to do.
The house needs a new boiler, so it’s a good time to think hard about the best approach to heating and cooling for the next 20. It needs a new roof so it’s the one chance they’ll get (for decades) to add insulation under the roofing. Is it worth it? 
Is now the time to add a solar electric system to stabilize long-term energy costs? A detailed energy evaluation will determine the answers to these and other questions.