I'd get it re-wired whether you "need" to or not if the alternative is various odd upgrades and extras.
Our electrics got a clean bill of health when we bought it 20 years ago (built 1979), so we just had the electrician put in a few extra sockets and wall lights etc. Still cost a couple of thousand as we had him back 3 times to do different things at £500-£750 per time whilst we were updating it.
Since then, the electrics have been no end of bother. Once the entire upstairs lighting would keep tripping. Had electrician back 3 times to try to diagnose the problem but eventually he had to admit defeat and he relaid a main cable to upstairs and disabled/rewired some external lights that had been fitted by a previous owner. Another £500 kerching!
Then we had a new kitchen fitted, which required a full re-wiring of the kitchen circuits as we wanted extra lighting and sockets. Another £500!
Throughout the period we've owned it, we've had "issues". The previous owner had put in some new sockets himself and somehow wired them across different circuits, causing some kind of feedback/looping issue which means we can't actually isolate any area of the house by tripping a circuit breaker manually - found that one out quite spectacularly when putting sockets back on the wall after replastering/decorating when the circuit breaker to that area was turned off (nothing worked when plugged into it), but still "blew" with flash and smoke when I accidentally touched two wires together whilst putting the socket back on.
Looking back, we wish we'd had it fully rewired when we moved in before we decorated and fitted new kitchen etc. As it is, it's ended up costing probably 2 or 3 times more with having to have electricians back over the years to sort things out, not to mention the mess and inconvenience (having to pull up new flooring to get to the wires/junctions boxes etc).