VACUUM and other maintenance work

Hello,

regarding the last messages dealing with losing data when not vacuum the
database regulary, I have some questions:

1. When I make the query "SELECT datname, age(datfrozenxid) FROM
pg_database;" I get the following result:

datname;age
test;1073742421
my_db;1073742732
template1;1073742548
template0;19741

Everytime I am repeating this query, the values are increasing by 5. I
thinks thats ok?

It is not possible to vacuum the template0 database because it is switched
of, and so I can't connect to the databse.
Does an overflow of the datfrozenxid in the template0 DB matter or cause
problems in any way?

2. Connecting, maybe by a cron job, to the database and submitting the query
"VACUUM ANALYZE" will prevent me from losing data from not vacuuming. Is
that correct?

3. Are there other things I should do regulary in order not to lose the data
in the database?

Thanks,

Christian