a hairdryer has a heating element and a fanmotor, the heating element is not a problem, but the fanmotor is made for 60 Hertz, so can burn-out
a mains adaptor for a battery charger , for a laptop, or for a cellular phone has a transformer in it and burns-out if it is only made for 60 Hertz
To-day's laptop adaptors are mostly made for the whole world and there is no problem as long as it states on the name-plate: 110-220 volt 50/60 Hertz, if it only states 110 volt 60 Hertz(cycles) it can not be used on a 50 Hertz mains, even if you connect it with a transformer let's say to use it in Europe on a 220 Volt 50 Hertz mains.
You can use a transformer to solve part ( the internal current can be lowered but the cycles cannot be changed) of the problem, by connecting the 60 cycles apparatus to a voltage 20% lower as mentioned on the nameplate
So a 110 volt 60 Hertz apparatus can be connected to a 50 Hertz mains on a voltage 20% lower then 110 volt=90 volt.