UNLESS something goes wrong with your home's electrics (or you get them checked by an electrician, which you should do every 10 years), it's hard to know if they're safe or not, but this is something you don't want to take any chances with.
Not only should old-fashioned fuse boxes, sockets, switches and wiring be replaced, but you may need to do electrical work as part of big home improvements, such as fitting a new kitchen, converting the loft, or changing the use of a room.
While it may be necessary, changing the electrics can be very dirty and disruptive. If often involves gouging out plaster to create channels for the cables and taking up the floors, making it hard to continue living there while the work's being done.
You can legally do some minor electrical work yourself (see www.planning portal.gov.uk or ask your local council's building control department if in doubt), but it's generally a good idea to get a qualified electrician in.
The easiest option is to employ an electrician who belongs to a 'competent person scheme', such as NICEIC (you can search for registered electricians at www.niceic.com).
They can self-certify that their work complies with building regulations (Part P covers electrical work and applies in England and Wales).
If your electrician doesn't belong to a competent person scheme and the work they've done must comply with building regulations, you'll have to pay a building control officer from the council to inspect it.
a good sparky wont ask you to pay up front , not even for materials
If they want payment before the job's finished, the best option is to pay them in instalments when they meet agreed targets, so you're not paying them for work they haven't done.
When they've finished, ask them for a certificate to prove that the work is safe and legal (building control can also issue this), which you may need when you sell your home.