Good Morning, Veke,
For film, following standard procedure should result in negatives which, when stored properly, have nearly unlimited life spans. The main thing is to fix properly and wash thoroughly. I'd recommend using HCA, mostly to keep washing times reasonable. Note that negatives which are well over a century old still exist in good condition, even though early photographers lacked chemicals with the purity and consistency of modern products and somewhat casual fixing and washing procedures were sometimes employed.
For prints, fixing and washing are also of primary importance. Use two fixing baths, splitting the total time between the two. With FB paper, HCA is almost a necessity, unless you like to use a lot of wash water. Selenium toning is often recommended, not so much for visual effect as for increased permanence.
If your interest in the topic extends significantly beyond the usual level, there's a lot of information available in a Google search.
Konical