After many years of solo walking and scrambling I unfortunately developed a heart condition; but didn't develop the concomitant condition of no longer wanting to do remote walks solo.
The thing is, if you get into serious difficulty, it's not you that's the main sufferer, but rather those that care for you - I experienced this first hand with a near fatal accident: I didn't find it too bad, but it was tremendously stressful for wife, kids, family and friends to observe me gently rapping on death's door.
So (very reluctantly) I agreed to get and carry a Personal Locator Beacon on walks. They're mainly intended for sailors, but the functionality (immediate notification of emergency and location) works just as well for walkers. It cost me £200, and for the peace of mind it bought the family I think it was excellent value. (I don't tell them much about what I do on scrambling expeditions, mind
).