I posted before about a compressor failure on my 3 ton heat pump system 8 months after a major repair where a new compressor was installed. I've gotten several estimates for repair and replacement and am trying to make an educated choice on how to proceed. The technician demonstrated to me how each of the 3 compressor (single phase) terminals where shorted to the compressor case.

I'm now looking at either a new system (R410A) or compressor replacement (R22) under parts-only warranty.

The new system is a "basic" system, no two-speed fans, or anything special. Just new outdoor unit, line set and indoor coil. I would get a 10 year parts/labor warranty with required yearly maintenance check. (That was the most economical option, there were bigger, pricier things they were glad to sell me.)

The fix would be new warrantied compressor, flush lines, refill coolant. Hope for the best. Because of my personal finances, I'm starting to lean towards the repair option.

My questions are:

If I go for the repair, what do I as a consumer need to do to maximize the chance that the repair will last? What do I need see the technician do?

Do I require them to do an acid test? If acid is present, what cost-effective corrective action should be taken?

I've seen internet ads for a "Qwikshot acid flush". They claim there is no salt residue that would otherwise contaminate my system. Should I want this product placed in the repaired system just to be sure the acid is gone if present?

Regarding add-on electric kits:

Will a hard-start kit really increase compressor longevity? Some ads claim that all motors used to have similar kits, but they were removed to save money, and claim that they reduce inrush current and correct power factor on all motors thus prolonging the life of the windings.

What about the Hyper Engineering soft-start kit? One Youtube HVAC vlogger promotes this kit for making a compressor last longer.

I'll be happy if I can get a repair that can be expected to last another 5 years or so. If that's an unreasonable expectation, I guess I'll finance a new system.