"I want to consolidate and make it part of my life whilst making...

"I want to consolidate and make it part of my life whilst making use of any testosterone I've got left."
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Rather than using up your testosterone the weight training will stimulate your body to produce more.It becomes more important/beneficial to stick with as we age.
One thing I would add to advice already given is to exercise the muscles that are your weak points if you intend to continue doing it long term(decades).That way you will be less likely to incur injuries.