Lead is undoubtedly a nasty metal. Its biological half-life is very long (10 years, cf. Hg’s 65 days), it is decently bioavailable (even in the metallic form, due to its softness), and chronic lead exposure has some pretty unpleasant symptoms. Yet, unfortunately, lead is also a major component in most electronics solder, especially in non-commercial settings.
Solder chemistry is very complex, and so there are many perfectly valid reasons why one would want to use leaded-solder. Sadly, it does seem that majority-tin solders are (on average) mechanically inferior to majority-lead alloys and suffer from issues such as tin pest - limiting their use to environments free from temperature extremes and strong vibrations. Of course, this isn’t really an issue for me, as I rarely design projects that need to function in such conditions and, when I do, the lifetime of solder joints is rarely the limiting factor for device reliability. Worrying about solder alloy properties for such applications just seems like premature optimization…
The real reason why so many seem to use leaded-solder is due to its lower melting point (182 C vs. > 210 C ) and lower surface tension - both factors that make soldering easier, especially when using a cheap iron with a bad tip and poor temperature control. All forum or blog discussions of the topic invariable turn into leaded-advocates claiming
I’m incapable of proficiently soldering without lead, and I haven’t been poisoned yet. I find this argument slightly infuriating and essentially baseless: a good craftsman neither blames their tools or materials.
Thus, the logical course of action seems simple: buy a new soldering iron, proper solder, and compensate for the slight increase in difficulty with a bit of practice.