Safety comes under so many different guises, whether it is lights or road position, potentially different routes. Lights generally come under accessories. There are usually some new ones each year and some favourites.
Mine normal set up (actually this will prompt me to get it ready as I noticed last week I may start to need it), is a Smart one at the back if I'm in the gloaming, two if it's actually going to be dark so that if it fades on route I've still got the other one. At the front my main one is a Hope light which is quite old now, and backed up with a second light.
Front lights fall into Two categories, to be seen, and to see. Where and when you ride will also affect which sort of lights you should get.