Avoid checked bags because if you’re travelling short haul it usually means LOTS of extra fees. While checked baggage is usually included for long haul journeys, it causes delays and heightens the risk of lost baggage.
Hefty luggage also limits your transport options to and from the airport- it’s much easier to use cheaper local buses and trains with a smallish backpack rather than a couple of large suitcases. Half a shoestring recently traveled around Indonesia and New Zealand for a month with a 25l backpack – it is possible! The recent Sweden trip was managed using a large handbag instead of a cumbersome overnight bag.