You seem you want to add 'H' or 'He' and a number based on the SpinEdits values.
Preserve the values of Merke variables in both procedures SpinEdit1Change and SpinEdit2Change by adding them to the form as two different names Merke1 and Merke2:
TForm2 = class(TForm)
...
public
Merke1, Merke2: string;
end;
Since both SpinEdit1Change and SpinEdit2Change do the same thing, have them call one common procedure:
procedure ProcessValue(var AMerke: String; AValue: integer; APrefix:String);
begin
if AValue<=0 then
AMerke := ''
else
begin
if AValue=1 then
AMerke := APrefix
else
AMerke := APrefix + AValue.ToString;
end;
end;
This way if the logic changes, you only need to deal with one procedure.
procedure TForm2.SpinEdit1Change(Sender: TObject);
begin
ProcessValue(Merke1, SpinEdit1.Value, 'H');
Label1.Caption := Merke1+Merke2;
end;
procedure TForm2.SpinEdit2Change(Sender: TObject);
begin
ProcessValue(Merke2, SpinEdit2.Value, 'He');
Label1.Caption := Merke1+Merke2;
end;