Came out to perform preventative maintenance on furnace for customer. Discussed with customer about maintenance being provided today, filters, and any issues she might be having. Customer stated that the filter may need to be changed, but isn’t sure. Other than that, the system stayed consistent through the cold front we had this week. I changed out customer supplied filter. Inspected the blower assembly, motor, capacitor, electrical components, heating components, heat exchanger and evaporator coil condition. Cleaned flame sensor and inducer port. Found blower assembly to be very dirty and in need of cleaning. Evaporator coil had some build up, but the blower assembly definitely needs to be pulled and cleaned. The hot surface ignitor is reading close to max ohms, and the furnace itself has some heat stress. Cycled system on and checked operation, amps, temperatures, gas pressure and CO. System is still operating properly at this time, but is in rough shape. Discussed repairs vs replac