Don’t believe just me about the benefits if high intensity interval training, have a look at someone else’s opinion.
The keys to success with strength training, once you respect the principle of never hurting yourself, can be found in two major guiding principles. Progressive overload and consistency. You need to gradually but surely increase the challenge or your body will have nothing to adapt to and obviously if you aren’t consistent, then the results won’t be there either. Unfortunate factoid: You can’t store either fitness or strength. Hence the advice above. Don’t stop, once you start.