NFS implementations have certainly improved, and certain sub-algorithms as well, e.g. lattice sieving and polynomial selection. But these things don't significa

NFS implementations have certainly improved, and certain sub-algorithms as well, e.g. lattice sieving and polynomial selection. But these things don't significantly tilt the exponent you expect in a factorization. As in, you expected around 2^80 "operations" for RSA-1024 back in 1995, and that's still roughly what you expect today. The practical NFS improvements since then might bring that down to 2^78 or even 2^72---and that's a lot of money saved---but when you're thinking of which key size to use it doesn't matter nearly as much as how 2^80 computation is something that is reasonably practical today, but was unthinkable in 1995.