Cricket tours are often long enough to reach the point where a visiting side wants nothing more than to return home. For Zimbabwe, that day probably came sooner than it should have in Bangladesh, where they lost all eight internationals they played.

As far as returns go, this is among Zimbabwe's more embarrassing. It is the second three-Test series they have been blanked in, after last playing in a rubber of that length a decade ago. Although they have been on the receiving end of more ODI series whitewashes before - 3-0 to South Africa this year and 5-0 to India last year are the most recent examples - and have also been guilty of losing every match on a tour - West Indies in 2013, New Zealand in 2012 - to have slipped to that level against the team they are supposed to be competitive against has taken Zimbabwe to a new low.

It has laid bare issues of inconsistency and instability and, with the World Cup looming, has left them more insecure than they usually are. To sum it up in a sentence, what Zimbabwe demonstrated in Bangladesh was that they are unable to stay in a game - any game - long enough to challenge for victory.

Like many teams in the lower tier of cricket's rankings, Zimbabwe's troubles begin at the top, where they have unable to find an opening combination that works. They tried four different combinations in the eight matches but could not manage anything more substantial than a first-wicket stand of 19 in the Tests and 48 in the ODIs. A glaring common denominator is Vusi Sibanda, whose future must now be examined. .

Sibanda is a stalwart of the Zimbabwe game whose career has stretched for more than a decade but he has yet to score a Test century. He has not managed a fifty in 17 innings and more than three years, and has gone 10 matches and 15 months without reaching the milestone in an ODI. He was put on notice earlier in the year when he was dropped against both Afghanistan and South Africa and the 104 runs he managed in six innings on this tour may have been the end of his rope.

Zimbabwe might be better served at the World Cup with Sikandar Raza and Hamilton Masakadza opening but will need a leap of faith to invest in someone else at No.3. They will also need more from Raza, who showed promise with three fifties in the Test series but could not transfer that form to the ODIs.

Masakadza did not have that problem. After a career-best 158 in the second Test, he was the second-highest run-scorer for Zimbabwe in the ODIs. He prefers to bat at one-drop but would likely be so keen to play in a World Cup after missing out on the last two that he would gladly open.

The temptation would be to persist with Sibanda at No.3, if only for the reassurance he provides as a regular, but Zimbabwe should have learnt the dangers of over-reliance from this trip. Their usual run-getter Brendan Taylor had a torrid Test series, with 135 runs in six innings, and Zimbabwe desperately needed more from him. They got that in the ODIs, where he scored two fifties and was their most successful batsman, but by then they should have had others contributing as well.

Between Taylor and Elton Chigumbura, Zimbabwe remain shaky. They have rotated through the likes of Craig Ervine, Richmond Mutumbami, Solomon Mire, Regis Chakabva and Malcolm Waller, but none of them have done enough or been given long enough to make a spot their own. Effectively, that means Zimbabwe always find themselves doing similar things when they bat. They have to recover from shaky starts and just as they find steady ground, they stumble again. For evidence, there is this tour. In six Test innings, they scored over 300 just twice and they could not get to 250 in any of the ODIs.

Then there are other problems like their techniques, which need sharpening against spin, particularly left-arm spin, and their temperaments, which falter because of a lack of regular game time. In the second Test, 16 of their 20 wickets went to the left-arm spinners. Zimbabwe have only played four Tests in the last 13 months, not nearly enough to learn how to bat for long periods.

The result is that Zimbabwe's attack seldom has anything substantial to work with but Tinashe Panyangara tries. He was their standout bowler of the tour, with 14 scalps at 20.28 in the Tests and nine wickets at 24.44 in the ODIs, but he lacks support. Natsai M'shangwe, the legspinner, was the next most incisive Test bowler but his seven wickets cost 435 runs, at 62.14 apiece. Malcolm Waller took six wickets but their other seamers struggled.

Tendai Chatara would have been a particular concern, with just three wickets in two Tests. He had a better ODI series with six wickets at 31.50 and will still be an important part of the long-term plans but Zimbabwe still need more. Chigumbura will provide will be one of the seamers who will carry a greater load at the World Cup. Zimbabwe's spin cupboard remains their best-stocked resource. Even without Prosper Utseya, they have choices that range from John Nyumbu to Tafadzwa Kamungozi and even when they are not taking wickers, they do a decent containing job.

That is one of the few positives Zimbabwe can pull out of a trip otherwise steeped in disappointment. Masakadza's maturity, Chakabva's coming of age with his maiden century and Taylor's return to form are other highlights. But on the whole, the Bangladesh visit would have dented Zimbabwe's already fragile confidence and left them with more questions than answers. They won't have much opportunity to confront all of them because they play no international cricket until next year's World Cup but what they will know is that when they get there, they not want to feel like they should have one foot in the boarding tunnel midway through the trip.

Firdose Moonda is ESPNcricinfo's South Africa correspondent