Do not be afraid of the semi-colon; it can be most useful. It marks a longer pause, a more definite break in the sense, than the comma; at the same time it says
"Here is a clause or sentence too closely related to what has gone before to be cut-off by a full-stop ".
The semi-colon is a stronger version of the comma. A frequent mistake is to use a comma where two clauses without a conjunction call for a stronger stop.
The Company is doing some work on this, it may need supplementing.
If it is your own pension please say what type it is, if it is your mother's then it need not be included in your income.
Each of these sentences needs a semi-colon in place of the comma.
The semi-colon is also useful for avoiding the rather dreary trailing participles with which writers often end their sentences:
The postgraduate teaching hospitals are essentially national in their outlook, their geographical situation being merely incidental.
An attempt to devise permanent machinery for consultation was unsuccessful, the initial lukewarm response having soon disappeared.
There is nothing faulty in the grammar or syntax of these sentences, and the meaning of each is unambiguous. But they have a tired look. They can be wonderfully freshened by using the semi-colon, and rewriting them:
The postgraduate teaching hospitals are essentially national in their outlook; their geographical situation is merely incidental.
An attempt to devise permanent machinery for consultation was unsuccessful; the initial lukewarm response soon disappeared.