procedure Tdm.ConnectionBeforeConnect(Sender: TObject);
const
  dbname = 'name.db';
var
  s: string;
  f: Boolean;
begin
  try
    s := TPath.Combine(ExtractFilePath(ParamStr(0)), dbname);
    Connection.ConnectionString:='DriverID=SQLite;Database=' + s;
    // валидация БД
    SQLiteValidate.Database := s;
    if FileExists(s) then
    begin
      SQLog('Валидация БД...');
      cs.Enter;
      try
        f := SQLiteValidate.CheckOnly;
      finally
        cs.Leave;
      end;
      if (not f) then
      begin
        SQLog('Внимание! БД повреждена');
      end
      else
        SQLog('БД в порядке');
    end;}
  except
    on e: Exception do
    begin
      SQLog(e.Message, True);
    end;
  end;
end;

procedure Tdm.ConnectionAfterConnect(Sender: TObject);
var
  s: string;
  f: Boolean;
begin
  try
    // создаем таблицы если не существуют
    sql :=
      'PRAGMA foreign_keys = off;' +
      'BEGIN TRANSACTION;' +
      // создаем таблицы
      'CREATE TABLE If Not Exists table1 (' +
      '    idx  INTEGER PRIMARY KEY ASC' +
      '                 UNIQUE' +
      '                 NOT NULL,' +
      '    name TEXT    NOT NULL' +
      ');' +
      ...
      // подтверждаем транзакцию
      'COMMIT TRANSACTION;' +
      'PRAGMA foreign_keys = on;'
      ;
    try
      cs.Enter;
      try
        Connection.ExecSQL(sql);
      finally
        cs.Leave;
      end;
    except
      on e: Exception do
      begin
        SQLog(e.Message, True);
      end;
    end;
    // заполняем таблицы значениями по умолчанию (если отсутствуют)
    FillDefaultValues;
    ClearTable(); // удаление старых записей
    Vacuum; // сжатие
  except
    on e: Exception do
    begin
      SQLog(e.Message, True);
      // raise Exception.Create(e.Message);
    end;
  end;
end;

procedure Tdm.Vacuum;
begin
  try
    ChkConnect;
    SQLog('Vacuum...');
    cs.Enter;
    try
      Connection.ExecSQL('VACUUM;');
    finally
      cs.Leave;
    end;
    SQLog(sOK);
  except
    on e: Exception do
    begin
      SQLog(e.Message, True);
    end;
  end;
end;

procedure Tdm.DataModuleDestroy(Sender: TObject);
var
  dt: TDateTime;
  dir: string;
begin
  try
    ClearTable;
    dt := Now;
    dir := TPath.Combine(ExtractFilePath(ParamStr(0)), 'backup');
    DbBackup(TPath.Combine(dir, Format('db_%.4u_%.2u_%.2u.bak', [YearOf(dt), MonthOf(dt), DayOf(dt)])));
  except
    on e: Exception do
    begin
      SQLog(e.Message, True);
    end;
  end;
  if Assigned(cs) then FreeAndNil(cs);
end;

procedure Tdm.DbBackup(const FileName: string);
var
  s: string;
begin
  try
    SQLog(Format('DbBackup (FileName = "%s")...', [FileName]));
    s := ExtractFilePath(FileName);
    if not DirectoryExists(s) then
    begin
      SQLog(Format('Создание папки: "%s"...', [s]));
      ForceDirectories(s);
      SQLog(sOK);
    end;
    SQLog('Создание резервной копии БД...');
    SQLiteBackup.Database := Connection.Params.Database;
    SQLiteBackup.DestDatabase := FileName;
    cs.Enter;
    try
      SQLiteBackup.Backup;
    finally
      cs.Leave;
    end;
    SQLog(sOK);
  except
    on e: Exception do
    begin
      SQLog(e.Message, True);
    end;
  end;
end;

The timeout (msecs) when FireDAC will remove connections unused more than POOL_ExpireTimeout time. Default value is 30000 msecs (30 secs). 

The time (msecs) after which the inactive connection may be deleted from the pool and destroyed. Default value is 90000 msecs (90 secs).